Cirrus clouds in the extratropical tropopause and lowermost stratosphere region

涉及卷云的过程在气候预测中造成的巨大不确定性突出了通过观测获得更多关于卷云的定量信息的重要性。尤其是在对流层顶附近，与较低和较厚的卷云相比，卷云可能有很大的变暖效应，只有很少的信息可用。地面激光雷达观测和卫星红外翼探测表明了一种新的卷云云，即平流层最低层(LMS)中卷云的存在，到目前为止，这种云的测量特征还不是很好，完全没有被全球模式研究考虑。拟议的研究Citros将根据2017年9月/10月拟议的Halo WISE任务期间的测量结果，研究热带外对流层顶和最低平流层地区的卷云。将特别着重分析使用新型GLORIA大气辐射成像极板观测仪对云结构进行测量的情况。由于它能够对红外波长区780到1400厘米-1的空气体积进行层析成像，它可以提供观测到的云结构的三维重建。由于沿视线的长翼路径积分，红外测深仪对测量光学薄卷云极为敏感。与基于Halo的激光雷达仪器Wales相结合，有效载荷将提供最灵敏的遥感测量，以确定对流层顶周围卷云的微观和宏观物理参数。与现场测量水蒸气和冰水含量一起，Halo WISE任务为对流层顶周围的云研究提供了一个高容量的有效载荷，并能够证明LMS中的云的存在。研究的一个主要部分将是开发新的检索技术，利用红外成像仪Gloria探索对流层顶周围的光学薄卷云。对层析云测量的分析将使其有可能恢复更好的受约束的微物理性质，如冰水含量或颗粒半径信息。化学拉格朗日平流层模型(CLAMS)和CLAMS的模型研究和预报将在详细研究活动之后提供。将研究气象条件对温带对流层顶和LMS地区冰粒形成的影响，或副热带急流混合过程与Rossby波破裂事件的相关性，以及与中高纬度LMS卷云的联系。与新的CLAMS-Ice模块一起，可以在个案研究中非常详细地研究LMS和对流层顶区域卷云的关键形成过程。

Large uncertainties in climate prediction caused by processes involving cirrus clouds highlight the importance of more quantitative information on cirrus clouds by observations. Especially around the tropopause, where cirrus may have a large warming effect in comparison to lower and thicker cirrus only very little information is available. Ground based lidar observations and satellite based IR limb sounding are suggesting a new class of cirrus clouds, the presence of cirrus in the lowermost stratosphere (LMS), which are so far not well characterised by measurements and not considered in global models studies at all.The proposed study CiTroS will investigate Cirrus clouds in extratropical Tropopause and lowermost Stratosphere region based on measurements during the proposed HALO mission WISE in Sep/Oct 2017. Special emphasis will be taken on the analysis of measurements of cloud structures with the novel Gimballed Limb Observer for Radiance Imaging of the Atmosphere (GLORIA) instrument. With its ability to image tomographically volumes of air in the IR wavelength region 780 to 1400 cm-1, it may provide a three-dimensional reconstruction of the observed cloud structures. IR limb sounders are extremely sensitive to measure optically thin cirrus clouds due to the long limb path integration along the line of sight. In combination with the HALO-based lidar instrument WALES the payload will present the most sensitive remote sensing measurements for the characterisation of micro- and macrophysical parameter of cirrus clouds around the tropopause. Together with the in situ measurement for water vapour and ice water content the HALO mission WISE represents a high-capacity payload for cloud studies around the tropopause and enables the proof of existence for clouds in the LMS. One major part of study will be the development of new retrieval techniques for the exploration of optically thin cirrus clouds around the tropopause with the IR imager GLORIA. The analysis of the tomographic cloud measurements will make it possible to retrieve much better constrained microphysical properties like ice water content or particle radius information.Model studies and forecasts form the Chemical Lagrangian Model for the Stratosphere (CLaMS) and CLaMS will be available after the campaign for detailed studies. Research questions regarding the impact of meteorological conditions on the formation of ice particles in the extratropical tropopause und LMS region, or the relevance of mixing processes at the subtropical jet in conjunction with Rossby wave breaking events and the link to cirrus clouds in the LMS at mid and high latitudes, will be investigated. Together with the new CLaMS-Ice module, which simulates formation and evolution of cirrus clouds along trajectories with a detailed double-moment bulk microphysical scheme, it is possible to investigate in case studies very detailed the key formation processes of cirrus in the LMS and tropopause region.