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

过氧基RO2*(=I[HO2]+[RO2])在大气化学中的重要性已得到充分证实。RO2*是寿命较短的物种，会产生寿命较长的辐射活性物质(如臭氧、臭氧)和化学或毒理上重要的污染物(如臭氧、过氧乙酰硝酸盐、CH3CO.O2、PAN、醛、酸等)。在垂直和远距离输送之后，这些物质反过来又在区域和全球的地球大气化学中发挥着重要作用。由于它们的低浓度，即使在地面上测量到的RO2*也很稀少。因此，我们测试自己对RO2*化学及其后果的理解的能力是有限的。和平行动的首要科学目标是通过优化新的测量技术，并结合边界层、自由对流层和UT/LS区域的其他关键物种对RO2*进行测量和分析，来解决这一缺陷。利用新的研究飞机HALO(高空远程)的独特能力，RO2*在确定臭氧丰度方面的作用将是一个重要的焦点。从边界层到UT/LS的RO2*的现场测量提供了关于这些过程的独特信息。在和平行动中，新的RO2*探测仪器PerCEAS(过氧基空腔增强吸收光谱仪)将在参与Halo-OMO(氧化机制观测)和Shiva/Hox-NOx-xox(平流层臭氧：变化大气中的卤素影响)测量活动之前，为在Halo上飞行进行优化。此外，将改进Halo-PerCEAS，以实现RO2*的形态形成和直接检测二氧化氮、NO2。该仪器还将用于测量自由基前体乙二醛(CHO.CHO)，这是在生物和人类排放以及生物质燃烧中形成的关键临时储存库。

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.