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

ENVISAT卫星上搭载的MIPAS仪器提供了独特的光谱辐射测量记录，该仪器复盖了全球平流层下层至中间层下层，特别是极地夜间区域。其运作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，通过比较MIPAS观测和KASIMA模式的结果，评估了平流层NOx值增加的化学影响，特别是对臭氧消耗的影响，以及对NOY预算的贡献。在该项目的第三阶段，将扩大数据基础，使用仪器的降低分辨率模式提供最多的观测数据，填补数据在时间和空间覆盖范围方面的空白，并调整和发展检索技术。利用扩展的数据集，将利用数据分析和模型模拟，针对更多的气象、太阳物理和地磁情况，分析太阳质子事件相对于极光活动对氮氧化物产生的作用，以及对极地冬季期间支配向下输送的动态情况的依赖。由于在第二个供资期内进行的模型相互比较显示，在对固相萃取过程中HNO3和ClONO2的积累的了解方面存在重大缺陷，将通过详细的观测和模型模拟来研究相关的NOx、Hox和氯化学。在与CAWSES其他伙伴的密切合作下，该项目旨在改进化学气候模型，使其能够将自然强迫模拟为太阳变率。

A unique record of spectral radiance measurements has been provided by the instrument MIPAS on-board the ENVISAT satellite which covers 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 chemical effects of increased stratospheric NOx values, especially on ozone depletion, and the contribution to the NOy budget has been assessed by comparing MIPAS observations and the results of the KASIMA model. During the third phase of the project the data basis will be extended by providing up to present observations using the reduced resolution mode of the instrument, by filling gaps in the time and spatial coverage of the data, and by adapting and developing retrieval techniques. Using the extended data set the role of solar proton events compared to auroral activity for NOx production and the dependence on the dynamic situation during polar winters ruling downward transport will be analysed for more meteorological, solarphysical and geomagnetical situations using data analysis and model simulations. As a model inter-comparison undertaken during the second funding period showed major deficits in the understanding of the build-up of HNO3 and ClONO2 during SPEs, related NOx, HOx and chlorine chemistry will be studied by detailed observation and model simulations. In close co-operation with other CAWSES partners the project aims to contribute to the improvement of chemical climate models with respect to their capability to simulate natural forcings as solar variability.