Brown M A J, Patel M R, Lewis S R, Holmes J A, Sellers G J, Streeter P M, Bennaceur A, Liuzzi G, Villanueva G L, Vandaele A C
The Open University Milton Keynes UK.
Space Science and Technology Department Science and Technology Facilities Council Rutherford Appleton Laboratory Oxfordshire UK.
J Geophys Res Planets. 2022 Nov;127(11):e2022JE007346. doi: 10.1029/2022JE007346. Epub 2022 Nov 10.
We show a positive vertical correlation between ozone and water ice using a vertical cross-correlation analysis with observations from the ExoMars Trace Gas Orbiter's Nadir and Occultation for Mars Discovery instrument. This is particularly apparent during = 0°-180°, Mars Year 35 at high southern latitudes, when the water vapor abundance is low. Ozone and water vapor are anti-correlated on Mars; Clancy et al. (2016, https://doi.org/10.1016/j.icarus.2015.11.016) also discuss the anti-correlation between ozone and water ice. However, our simulations with gas-phase-only chemistry using a 1-D model show that ozone concentration is not influenced by water ice. Heterogeneous chemistry has been proposed as a mechanism to explain the underprediction of ozone in global climate models (GCMs) through the removal of HO . We find improving the heterogeneous chemical scheme by creating a separate tracer for the HO adsorbed state, causes ozone abundance to increase when water ice is present (30-50 km), better matching observed trends. When water vapor abundance is high, there is no consistent vertical correlation between observed ozone and water ice and, in simulated scenarios, the heterogeneous chemistry has a minor influence on ozone. HO , which are by-products of water vapor, dominate ozone abundance, masking the effects of heterogeneous chemistry on ozone, and making adsorption of HO have a negligible impact on ozone. This is consistent with gas-phase-only modeled ozone, showing good agreement with observations when water vapor is abundant. Overall, the inclusion of heterogeneous chemistry improves the ozone vertical structure in regions of low water vapor abundance, which may partially explain GCM ozone deficits.
我们利用与ExoMars微量气体轨道器的火星发现仪的天底和掩星观测数据进行的垂直互相关分析，展示了臭氧与水冰之间存在正的垂直相关性。这在火星年35度、南纬高纬度地区、水汽丰度较低且相位角为0°至180°时尤为明显。在火星上，臭氧与水汽呈反相关；克兰西等人（2016年，https://doi.org/10.1016/j.icarus.2015.11.016）也讨论了臭氧与水冰之间的反相关关系。然而，我们使用一维模型仅进行气相化学模拟表明，臭氧浓度不受水冰影响。非均相化学被认为是一种机制，可通过去除羟基自由基来解释全球气候模型（GCMs）中臭氧预测不足的问题。我们发现，通过为吸附态的羟基自由基创建一个单独的示踪剂来改进非均相化学方案，当存在水冰（30 - 50千米）时，臭氧丰度会增加，能更好地匹配观测趋势。当水汽丰度较高时，观测到的臭氧与水冰之间不存在一致的垂直相关性，并且在模拟场景中，非均相化学对臭氧的影响较小。水汽的副产物羟基自由基主导了臭氧丰度，掩盖了非均相化学对臭氧的影响，使得羟基自由基的吸附对臭氧的影响可以忽略不计。这与仅进行气相模拟的臭氧结果一致，表明在水汽丰富时与观测结果吻合良好。总体而言，纳入非均相化学改善了水汽丰度低的区域的臭氧垂直结构，这可能部分解释了GCM中臭氧的不足。
