Radiative and energetic constraints on the global annual mean atomic oxygen concentration in the mesopause region
Radiative and energetic constraints on the global annual mean atomic oxygen concentration in the mesopause region
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DOI：
10.1002/jgrd.50400
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发表时间：
2013-06
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通讯作者：
M. Mlynczak;Linda H. Hunt;C. Mertens;B. Marshall;J. Russell;Manuel López Puertas;Anne K. Smith;D. Siskind;J. Mast;R. Thompson;L. Gordley
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作者：
M. Mlynczak;Linda H. Hunt;C. Mertens;B. Marshall;J. Russell;Manuel López Puertas;Anne K. Smith;D. Siskind;J. Mast;R. Thompson;L. Gordley
我们提出了一种新方法来限制和验证中层顶区域（约 80 至约 100 公里）的原子氧 (O) 浓度。在之前的一篇配套论文 [Mlynczak 等人，] 中，我们提出了中层顶区域的 O 原子浓度，该浓度是通过使用宽带发射辐射测量 (SABRE) 仪器对大气进行探测来测量白天臭氧和夜间羟基排放率而推断出来的。这里提出的方法使用全球年平均能量平衡的约束来推导原子氧浓度，与二氧化碳 (CO2) 辐射冷却速率和分子氧 (O2) 引起的太阳加热速率一致。在全球年平均基础上，这些冷却和加热速率之间的数学差异有效地限制了所有其他过程总和的最大加热速率。其余项，即臭氧引起的太阳加热加上一系列放热化学反应，可以表示为 O 的函数。这种新方法可以实现简单的数学表达式，从而产生中层顶区域全球年平均“辐射约束”原子氧的垂直剖面。辐射约束的原子氧仅取决于 CO2 冷却速率、O2 太阳能加热速率以及标准反应速率系数和焓。这些分析中使用的辐射冷却和太阳能加热率源自 NASA 热层、电离层、中间层能量学和动力学卫星上的 SABRE 仪器进行的测量。 SABRE 辐射约束原子氧与大部分中层顶区域的 SABRE 臭氧和 OH 排放测量得出的结果非常一致。辐射约束的原子氧代表了中层顶区域全球平均氧原子浓度的上限。
We present a new approach to constrain and validate atomic oxygen (O) concentrations in the mesopause region (~ 80 to ~ 100 km). In a prior companion paper [Mlynczak et al., ], we presented O‐atom concentrations in the mesopause region inferred from measurements of day ozone and night hydroxyl emission rates made by the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument. The approach presented here uses the constraint of global, annual mean energy balance to derive atomic oxygen concentrations, consistent with rates of radiative cooling by carbon dioxide (CO2) and solar heating due to molecular oxygen (O2). The mathematical difference between these cooling and heating rates, on a global annual mean basis, effectively constrains the maximum heating rate for the sum of all other processes. The remaining terms, solar heating due to ozone plus a series of exothermic chemical reactions can be expressed as functions of O. This new approach enables a simple mathematical expression that yields the vertical profile of global annual mean “radiatively constrained” atomic oxygen in the mesopause region. The radiatively constrained atomic oxygen depends only on the CO2 cooling rates, O2 solar heating rates, and standard reaction rate coefficients and enthalpies. Radiative cooling and solar heating rates used in these analyses are derived from measurements made by the SABER instrument on the NASA Thermosphere Ionosphere Mesosphere Energetics and Dynamics satellite. There is excellent agreement between the SABER radiatively constrained atomic oxygen and that derived from the SABER ozone and OH emission measurements over most of the mesopause region. Radiatively constrained atomic oxygen represents an upper limit on the global average O‐atom concentration in the mesopause region.