On the formation of HNO3 in the Antarctic mid to upper stratosphere in winter
On the formation of HNO3 in the Antarctic mid to upper stratosphere in winter
复制标题
冬季南极平流层中上层HNO3的形成
DOI：
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发表时间：
2001
期刊：
影响因子：
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通讯作者：
S. Smyshlyaev
中科院分区：
文献类型：
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作者：
R. L. Zafra;S. Smyshlyaev
我们解决了以前未解决的在极地冬季平流层中上层形成硝酸的难题，该难题首次由1978-1979年北极冬季平流层的近缘红外监测仪观测到。在过去的20年里，一些理论研究试图重现这些观察结果，取得了不同程度的成功。最近，在1993年、1995年和1999年的南极冬季，通过UARS上的低温翼阵标准龙光谱仪和在南极进行的一系列地面观测，已经澄清了形成过程的开始、高度范围和持续时间。使用石溪- sst。在二维光化学模型中，我们通过离子簇化学和非均相化学对硫酸盐气溶胶中HNO3的形成进行了重新探索。通过纳入我们认为是来自中间层的实际NOy通量，我们发现该模式可以通过平流层中上层离子簇增强的化学组合产生观测到的混合比，并通过在~ 40 km以下的硫酸盐气溶胶上的非均相化学增强。结果阐明了各种过程的相对作用和假设的NOy通量。这也表明，需要在用于模拟极地平流层的模式中纳入更精确的向下NOy通量。最后，我们强调需要考虑NOy或NOx重新分配到HNO3的影响，在冬季和早春观测到的NOy到达平流层中下层的量的变化可以适当地用作反映热层-中间层NOy产生或运输变化的示踪剂。
We address the previously unresolved puzzle of nitric acid formation in the polar winter mid to upper stratosphere, first indicated by Limb Infrared Monitor of the Stratosphere observations in the Arctic winter of 1978–1979. Several theoretical studies over the past 2 decades have tried to reproduce these observations with varying success. More recently, the onset, altitude range, and duration of the formation process have been clarified by the Cryogenic Limb Array Etalon Spectrometer onboard UARS and by a series of ground-based observations taken at the South Pole during the Antarctic winters of 1993, 1995, and 1999. Using the Stony Brook-SSt. Petersburg two-dimensional photochemical model, we have reexplored HNO3 formation via both the ion cluster chemistry and heterogeneous chemistry on sulfate aerosols considered by earlier investigators. By including what we believe to be a realistic flux of NOy from the mesosphere, we find that the model can generate observed mixing ratios through a combination of ion-clusterenhanced chemistry in the upper to mid stratosphere, augmented by heterogeneous chemistry on sulfate aerosol below ∼40 km. Results are presented which clarify the relative role of various processes and assumed NOy fluxes. These also point up the need to incorporate more accurate downward NOy fluxes in models being used to simulate the polar stratosphere. Finally, we emphasize the need to consider the influence of repartitioning of NOy or NOx into HNO3 before observed variations in amounts of the former reaching the mid to lower stratosphere in winter and early spring can properly be used as tracers to reflect variations in thermospheric-mesospheric NOy production or transport.