HEPPA-II model–measurement intercomparison project: EPP indirect effects during the dynamically perturbed NH winter 2008–2009
HEPPA-II model–measurement intercomparison project: EPP indirect effects during the dynamically perturbed NH winter 2008–2009
复制标题
HEPPA-II 模型测量比对项目：2008-2009 年动态扰动的 NH 冬季期间 EPP 间接影响
DOI：
10.5194/acp-17-3573-2017
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发表时间：
2016
影响因子：
6.3
通讯作者：
V. Yushkov
中科院分区：
文献类型：
--
作者：
B. Funke;W. Ball;S. Bender;A. Gardini;V. Harvey;A. Lambert;M. López‐Puertas;D. Marsh;Katharina Meraner;H. Nieder;S.;K. Pérot;C. Randall;T. Reddmann;E. Rozanov;H. Schmidt;A. Seppälä;M. Sinnhuber;T. Sukhodolov;G. Stiller;N. Tsvetkova;P. Verronen;S. Versick;T. Clarmann;K. Walker;V. Yushkov
摘要。我们比较了2008/2009年北半球（NH）极地冬季期间，三种高顶（上盖在120 公里以上）和五种中顶（上盖在80 公里左右）大气模式的模拟结果，以及来自七种卫星仪器（SciSat上的ice - fts、GOMOS、MIPAS和SCIAMACHY上的Envisat、MLS上的Aura、SABER上的TIMED和Odin上的SMR）的奇氮（NOx = NO + NO2）、温度和一氧化碳的观测结果。比较的模式包括三维化学输送模式3dCTM、ECHAM5/凌乱大气化学（EMAC）模式、FinROSE、中性和电离大气汉堡模式（HAMMONIA）、卡尔斯鲁厄中层大气模拟模式（KASIMA）、太阳气候臭氧链接研究的建模工具（SOCOL和CAO-SOCOL）和全大气群落气候模式（WACCM4）。对比的重点是高能粒子降水（EPP）的间接效应，即极冬季NOx的下降主要是由中间层和低层热层的EPP产生的。特别强调了2009年1月平流层突然变暖（SSW）和随后与中间层空气下降增强相关的平流层顶升高（ES）事件的影响。化学气候模式的模拟已经被推向对流层和平流层的再分析数据，而上面的数据不受限制。由MIPAS观测得到的氮奇上边界条件进一步应用于中顶模式。大多数模式都能很好地反映2008/2009年北半球冬季无扰动（ssw前）期间的中间层示踪剂下降，特别是EPP的间接影响。观测到的氮氧化物下降到较低的中间层和平流层，一般在20% %内重现。少数模式模拟的较大差异可以追溯到模式重力波阻力方案对极地冬季经向环流的影响，或者是模式最上层规定的NOx混合比和低垂直分辨率的组合。然而，在ES事件发生后的3 - 4月，模拟的中间层和平流层NOx分布明显偏离观测值。在大多数模拟中遇到的过快和过早的NOx舌向下传播，与中间层下层的温度高偏差（0.2-0.05 hPa）相吻合，这可能是由于对下降速度的高估造成的。相反，在ES事件开始后，中高层温度（0.05-0.001 hPa）通常被高顶模式低估，这表明下降太慢，因此NOx通量过低。因此，这些模型通常低估了模拟的氮氧化物舌的大小。中顶模式模拟的氮氧化物下降量平均更接近观测值，但显示出很大的差异，最高可达几百倍。这主要归因于不同的垂直模型域，其中应用了氮氧化物上边界条件。总的来说，相互比较表明，最先进的大气模式能够在动态和地磁静止的北半球冬季条件下再现EPP的间接影响。然而，在2009年北半球冬季扰动阶段，观测到的和模拟的NOx、CO和温度分布之间的差异，强调了在平流层顶升高事件的动力学表征中改进模式的必要性，以便更好地描述在这些特定条件下EPP的间接效应。
Abstract. We compare simulations from three high-top (with upper lid above 120 km) and five medium-top (with upper lid around 80 km) atmospheric models with observations of odd nitrogen (NOx = NO + NO2), temperature, and carbon monoxide from seven satellite instruments (ACE-FTS on SciSat, GOMOS, MIPAS, and SCIAMACHY on Envisat, MLS on Aura, SABER on TIMED, and SMR on Odin) during the Northern Hemisphere (NH) polar winter 2008/2009. The models included in the comparison are the 3-D chemistry transport model 3dCTM, the ECHAM5/MESSy Atmospheric Chemistry (EMAC) model, FinROSE, the Hamburg Model of the Neutral and Ionized Atmosphere (HAMMONIA), the Karlsruhe Simulation Model of the Middle Atmosphere (KASIMA), the modelling tools for SOlar Climate Ozone Links studies (SOCOL and CAO-SOCOL), and the Whole Atmosphere Community Climate Model (WACCM4). The comparison focuses on the energetic particle precipitation (EPP) indirect effect, that is, the polar winter descent of NOx largely produced by EPP in the mesosphere and lower thermosphere. A particular emphasis is given to the impact of the sudden stratospheric warming (SSW) in January 2009 and the subsequent elevated stratopause (ES) event associated with enhanced descent of mesospheric air. The chemistry climate model simulations have been nudged toward reanalysis data in the troposphere and stratosphere while being unconstrained above. An odd nitrogen upper boundary condition obtained from MIPAS observations has further been applied to medium-top models. Most models provide a good representation of the mesospheric tracer descent in general, and the EPP indirect effect in particular, during the unperturbed (pre-SSW) period of the NH winter 2008/2009. The observed NOx descent into the lower mesosphere and stratosphere is generally reproduced within 20 %. Larger discrepancies of a few model simulations could be traced back either to the impact of the models' gravity wave drag scheme on the polar wintertime meridional circulation or to a combination of prescribed NOx mixing ratio at the uppermost model layer and low vertical resolution. In March–April, after the ES event, however, modelled mesospheric and stratospheric NOx distributions deviate significantly from the observations. The too-fast and early downward propagation of the NOx tongue, encountered in most simulations, coincides with a temperature high bias in the lower mesosphere (0.2–0.05 hPa), likely caused by an overestimation of descent velocities. In contrast, upper-mesospheric temperatures (at 0.05–0.001 hPa) are generally underestimated by the high-top models after the onset of the ES event, being indicative for too-slow descent and hence too-low NOx fluxes. As a consequence, the magnitude of the simulated NOx tongue is generally underestimated by these models. Descending NOx amounts simulated with medium-top models are on average closer to the observations but show a large spread of up to several hundred percent. This is primarily attributed to the different vertical model domains in which the NOx upper boundary condition is applied. In general, the intercomparison demonstrates the ability of state-of-the-art atmospheric models to reproduce the EPP indirect effect in dynamically and geomagnetically quiescent NH winter conditions. The encountered differences between observed and simulated NOx, CO, and temperature distributions during the perturbed phase of the 2009 NH winter, however, emphasize the need for model improvements in the dynamical representation of elevated stratopause events in order to allow for a better description of the EPP indirect effect under these particular conditions.