PEroxy rAdicals measured by OF-Cavity Enhanced spectroscopy in the free troposphere with a focus on the upper troposphere / lower stratosphere (PEACE)

过氧自由基RO 2 *（=I[HO 2]+[RO 2]）在大气化学中的重要性已得到充分证实。RO 2 * 是寿命短的物质，其产生寿命较长的辐射活性（例如臭氧、O3）和化学或毒理学上重要的污染物（例如O3、过氧乙酰硝酸盐、CH3CO.O2.NO2、PAN、醛、酸等）。在垂直和远距离迁移之后，这些物质又在区域和全球的地球大气化学中发挥重要作用。由于其浓度较低，即使在地面上对RO 2 * 的测量也很少。因此，我们测试我们对RO 2 * 化学及其后果的理解的能力有限。PEACE的首要科学目标是通过优化新的测量技术以及结合边界层、自由对流层和UT/LS区域中的其他关键物种对RO 2 * 进行测量和分析来解决这一缺陷。RO 2 * 在确定O3丰度方面的作用将是一个重要的焦点，利用新的研究飞机HALO（高海拔远程）的独特能力。从边界层到UT/LS的RO 2 * 的现场测量提供了关于这些过程的独特信息。在PEACE内，新的RO 2 * 探测仪器PerCEAS（过氧自由基空腔增强吸收光谱仪）将在参加HALO-OMO（氧化机制观测）和SHIVA/HOx-NOx-XOx（平流层臭氧：卤素对不同大气的影响）测量活动之前，针对HALO上的飞行进行优化。此外，HALO-PerCEAS将得到改进，以实现RO 2 * 的形态分析和二氧化氮NO2的直接检测。该仪器还将用于测量自由基前体乙二醛（CHO.CHO），这是一种关键的临时储存库，在生物源和人为排放以及生物量燃烧中形成。

The importance of peroxy radicals, RO2* (=I[HO2]+[RO2]) in atmospheric chemistry is well established. RO2* are short lived species, which generate longer lived radiatively active (e.g. ozone, O3) and chemically or toxicologically important pollutants (e.g. O3, peroxyacetyl nitrate, CH3CO.O2.NO2, PAN, aldehydes, acids etc.). Following vertical and long-range transport, these in turn play a significant role in the chemistry of the earth’s atmosphere both regionally and globally. As a result of their low concentrations, measurements of RO2* even at the ground are sparse. Thus our ability to test our understanding of RO2* chemistry and its consequences has been limited. The overarching scientific objective of PEACE addresses this deficit by the optimization of a new measurement technique and by making and analyzing measurements of RO2* in combination with other key species in the boundary layer, the free troposphere and the UT/LS region. The role of RO2* in determining O3 abundance will be one important focus, utilizing the unique capability of the new research aircraft HALO (High Altitude Long Range). In-situ measurements of RO2* from the boundary layer to the UT/LS provide unique information about these processes. Within PEACE the new RO2* detection instrument PerCEAS (Peroxy radical Cavity Enhanced Absorption Spectrometer) will be optimised for flight on HALO, prior its participation in the HALO-OMO (Oxidative Mechanisms Observations) and SHIVA/HOx-NOx-XOx (Stratospheric ozone: Halogen Impacts in a Varying Atmosphere) measurement campaigns. In addition HALO-PerCEAS will be improved to enable the speciation of RO2* and the direct detection of nitrogen dioxide, NO2. The instrument will also be adapted to measure the radical precursor, glyoxal (CHO.CHO), a key temporary reservoir, formed in both biogenic and anthropogenic emissions and biomass burning.