Middle Atmosphere NOx variations and solar UV VAriability: Examples to study mesospheric/stratospheric coupling and the impact of solar variability on stratospheric ozone

太阳变率通过高能粒子相互作用引起的氮氧化物变化和太阳紫外线通量的变化对平流层臭氧的影响将通过观测和数值模拟的详细比较进行研究。ENVISAT卫星上的MIPAS仪器提供了光谱辐射测量的独特记录，该仪器覆盖全球平流层下层至中间层下层，特别是极地夜间地区。它运行的头两年包括不同阶段的太阳活动，包括2003年10月的太阳风暴。根据这些观测结果，将研究太阳活动产生的NOx与中间层示踪剂CO、H2 O和CH4一起向下运移。此外，观测所得的NOy、ClOx和臭氧将有助于研究NOx值增加的化学效应，特别是对臭氧消耗的影响，以及它们对NOy预算的贡献。CLaMS和KASIMA模式将用观测到的低层中间层NOx和示踪剂初始化，并将研究向下输送和混合过程，特别是在极地涡旋中。这可以通过粒子相互作用来估计与N2O光解相比较的NOx产量。利用光谱分辨的太阳紫外线数据，KASIMA模式将确定太阳紫外线变率的影响，并验证其光化学响应。该项目的结果将有助于用气候模型验证太阳周期研究。

The impact of solar variability on stratospheric ozone through NOx variations caused by energetic particle interaction and variations of the solar UV flux will be studied by detailed comparisons of observations and numerical simulations. A unique record of spectral radiance measurements has been provided by the instrument MIPAS on-board the ENVISAT satellite which cover the lower stratosphere up to the lower mesosphere globally and, in particular the polar night regions. The first two years of its operation encompassed phases of varying solar activity including the solar storm in October 2003. From these observations, the downward transport of NOx produced by solar activity together with mesospheric tracers as CO, H2 O and CH4 will be studied. Moreover, NOy, ClOx species and ozone from the observations will allow to study the chemical effect of increased NOx values, especially on ozone depletion, and their contribution to the NOy budget. The models CLaMS and KASIMA will be initialized with observed lower mesospheric NOx and tracers, and the downward transport and mixing processes will be studied, in particular in the polar vortices. This allows to estimate the NOx production via particle interaction compared to N2O photolysis. Using spectrally resolved solar UV data, the effects of solar UV variability will be identified with the KASIMA model and its photochemical response will be validated. The outcome of the project will help to validate solar cycle studies with climate models.