IRFP: The Impact of the Double Tropopause on the Composition of the Upper Troposphere and Lower Stratosphere

国际研究奖学金计划使美国科学家和工程师能够在国外进行9至24个月的研究。该计划的奖项提供了联合研究的机会，以及使用独特或互补的设施，专业知识和国外的实验条件。Peevey与德国于利希研究中心的Paul Konopka博士合作。在对流层上部和平流层下部（UTLS）区域的地球大气垂直结构中可以看到多个稳定层，通常称为双对流层顶。UTLS是地球大气的一个关键区域，因为它包含各种重要的辐射物质，例如水蒸气、臭氧和气溶胶，随着时间的推移，由于其他绿色温室气体（GHG）增加，地球表面逃逸的长波辐射减少，这些物质受到扰动。双对流层顶最常在中纬度地区形成，并与UT和LS之间的空气质量交换有关。空气质量交换事件可以通过调整当地温度廓线和该地区的静态稳定性来改变当地的辐射平衡，这反过来又可以改变大气结构，导致中纬度风暴路径向极移动。评估对流层顶相关的双重输送对UTLS区域辐射重要物种的分布和再分布的影响，对于理解和预测地球辐射收支，进而对气候和气候变化具有重要意义。本研究项目将利用高分辨率动态临边探测器（HIRDLS）、美国航天局Aura卫星上的一台仪器，以及德国于利希研究中心开发的平流层化学拉格朗日模型的模型模拟。该项目的第一个目标是确定双对流层顶内的空气来源，因为它可能会改变UTLS的组成，从而改变地球的辐射预算。第二个目标是了解双对流层顶和对流层顶逆温层（TIL）之间的关系，最近提出的其他科学家使用干大气模式的关系。该研究发现，没有TIL存在，双重对流层顶就无法形成。这种联系是出乎意料的，因为这两个大气特征具有相反的空间偏好和季节周期，因此，高垂直分辨率的观测和专门用于UTLS的模式将被用来探索这种关系。除了增加对UTLS地区和地球气候的了解之外，该项目的另一个好处包括PI和德国的主办机构之间的专业知识交流。Peevey博士将通过获得拉格朗日模型的知识和运行模型模拟的技能，从交流中受益匪浅。

The International Research Fellowship Program enables U.S. scientists and engineers to conduct nine to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad.This award will support a twelve-month research fellowship by Dr. Tanya R. Peevey to work with Dr. Paul Konopka at Forschungszentrum Jülich in Jülich, Germany.Multiple stable layers, usually called a double tropopause, are seen in the vertical structure of the Earth's atmosphere within the upper troposphere lower stratosphere (UTLS) region. The UTLS is a key region of the Earth's atmosphere since it contains various radiatively important species, e.g. water vapor, ozone and aerosols, which have been perturbed over time due to less long-wave radiation escaping from the Earth surface as other green house gases (GHGs) increase. The double tropopause forms most frequently in the mid-latitudes and has been associated with an exchange of air masses between the UT and LS. Air mass exchange events can change the local radiative balance by adjusting the local temperature profile and the static stability of the region, which in turn can change the structure of the atmosphere and result in a poleward shift the midlatitude storm tracks for example. Evaluating the impact of double tropopause related transport on the distribution and redistribution of radiatively important species in the UTLS region is important for understanding and predicting the Earth's radiation budget and, consequently, climate and climate change.This research project will study the UTLS region of the Earth's atmosphere using a unique combination of satellite observations from the High Resolution Dynamic Limb Sounder (HIRDLS), an instrument on the NASA Aura satellite, and model simulations from the Chemistry Lagrangian Model of the Stratosphere (CLaMS), developed at Forschungszentrum Jülich in Germany. The first objective of this project is to establish where air within the double tropopause originates since it could change the composition of the UTLS and thus Earth's radiative budget. The second objective is to understand the relationship between the double tropopause and tropopause inversion layer (TIL), a relationship recently put forth by other scientists using a dry-atmosphere model. That study found that the double tropopause could not form without the TIL being present. This connection is unexpected since these two atmospheric features have opposite spatial preferences and seasonal cycles, thus observations with high vertical resolution and a model specialized for the UTLS will be used to explore this relationship.Another benefit of this project, in addition to an increased understanding of the UTLS region and Earth's climate, includes the exchange of expertise between the PI and the host institution in Germany. Dr. Peevey will benefit greatly from the exchange by gaining knowledge of lagrangian models and skills in running model simulations.