Data assimilation and model calculations to study chemistry climate interactions and solar impact in the polar stratosphere - Phase 2 (DACCS)

该项目将借助卫星臭氧观测的数据同化和耦合化学气候模式(CCM)积分的分析，研究极地平流层臭氧与大气动力学之间的相互作用。重点将放在极地平流层的初冬臭氧及其与冬季晚些时候的气象条件和春季臭氧总量的关系上。结果表明，秋季和初冬极地平流层臭氧与春季高纬度臭氧总量之间存在着出乎意料的强相关。同样，冬初臭氧与冬春季晚些时候的气象条件也存在着密切的相关性。这种关系的机制目前尚不清楚。此外，有一些证据表明，在初冬，太阳可能会对极地平流层臭氧产生巨大影响。在这里，我们将详细分析全球平流层臭氧长期数据集，该数据集目前正在DACCS项目第一阶段内通过将SBUV(/2)卫星观测同化到一个化学传输模型中而创建。我们将特别分析导致秋季极地臭氧年际变化和冬季臭氧异常持续的机制。为了研究异常在氮物种中的可能作用，我们将扩大同化范围，包括从HALOE/UARS仪器观测到的氮氧化物(NOx)。我们将分析现有的化学气候模式积分，并将使用大气环流模式进行一系列额外的敏感性运行，以测试臭氧异常对行星波通量的影响的某些假设。

This project will investigate the interaction between ozone and atmospheric dynamics in the polar stratosphere with the help of data assimilation of satellite ozone observations and analyses of coupled chemistry climate model (CCM) integrations. There will be a focus on early winter ozone in the polar stratosphere and its relation to meteorological conditions later during winter and total ozone during spring. It has been shown that there exists an unexpectedly strong correlation between polar stratospheric ozone in autumn and early winter and total ozone at high latitudes during spring. Similarly, there exists a close correlation between early winter ozone and meteorological conditions later during winter and spring. The mechanisms for this relation are currently unclear. Moreover, there is some evidence for a possible large solar impact on polar stratospheric ozone in early winter. Here we will analyse in detail a global long-term data set of stratospheric ozone, that is currently being created within the first phase of the DACCS project through the assimilation of SBUV(/2) satellite observations into a chemical transport model. We will in particular analyse the mechanisms that lead to the inter-annual variability of polar ozone during autumn and the persistence of ozone anomalies over the winter. In order to investigate a possible role of anomalies in nitrogen species, we will extend the assimilation to include observations of nitrogen oxides (NOx) from the HALOE/UARS instrument. We will analyse existing chemistry climate model integrations and will perform a set of additional sensitivity runs with a general circulation model to test certain hypotheses of the influence of ozone anomalies on the flux of planetary waves.