Measurements Addressing Quantitative Ozone Loss, Polar Stratospheric Cloud Nucleation, and Large Polar Stratospheric Particles during Austral Winter and Spring

该提案寻求在2005年之前继续在南极洲上空对气球携带的臭氧进行现场观测。由于向大气中引入了大量的氯氟烃，南极平流层中的臭氧今天遭受着与过去大不相同的季节周期。在过去，南极的臭氧层数量主要由全球环流过程控制，导致冬季臭氧的积累。今天，氯的存在加上形成平流层云的低温，导致春季臭氧的最低值，这是因为臭氧和在云层颗粒表面被激活的氯之间的催化反应。导致臭氧丧失的机制一直是许多科学活动的主题，并已取得重大进展；然而，仍然存在悬而未决的问题，需要麦克默多站进行额外的臭氧和平流层粒子剖面测量。臭氧廓线测量将在南半球春季期间每隔3天完成一次，这将有助于为平流层氯负荷最大的时期提供观测基础。这将有助于建立所需的测量基础，以便在未来十年内随着平流层氯的减少观察臭氧恢复的第一批迹象。臭氧垂直廓线的测量将是用来观察平流层氯减少后随高度变化的第一批恢复迹象的重要工具之一。2003年，拟与几位欧洲同事合作开展一项国际南极竞赛活动，以获得与海拔有关的详细臭氧损失率测量结果，以便与化学输送模型和光化学盒子模型进行比较。此外，将继续对极地平流层云进行观测，以解决与硝酸水合物成核、南极平流层云内大颗粒的存在及其在反硝化作用中的作用以及极地平流层云颗粒的折射率有关的问题。气球上的仪器将提供高分辨率的轨迹测量，可用于评估气球温度历史的准确性。这些信息，加上现场的气溶胶剖面测量和微物理模型，将被用来测试各种PSC成核假说，这些假说对氯的活化和反硝化有直接影响。该仪器将在NSF的重大研究基础设施仪器开发奖的支持下开发。

The proposal seeks the continuation of in situ balloon-borne ozone observations over Antarctica through 2005. Ozone in the Antarctic stratosphere suffers a much different seasonal cycle today than it has in the past due to the introduction of significant amounts of chlorofluorocarbons into the atmosphere. In the past Antarctic ozone amounts were controlled primarily by global circulation processes leading to wintertime build up of ozone. Today the presence of chlorine coupled with cold temperatures, which create stratospheric clouds, leads to a springtime minimum in ozone due to a catalytic reaction between ozone and chlorine that has been activated on surfaces of the cloud particles. The mechanisms leading to this ozone loss has been the subject of much scientific activity and significant progress has been made; however, open questions remain which require additional ozone and stratospheric particle profile measurements from McMurdo Station. The ozone profile measurements, to be completed about every 3 days during austral spring, will contribute to the observational base for the period of maximum chlorine loading in the stratosphere. This will contribute to the measurement base required to observe the first signs of ozone recovery as stratospheric chlorine declines within the next decade. Measurements of vertical ozone profiles will be one of the important tools used to observe the first signs of the altitude dependent recovery following the decline in stratospheric chlorine. In 2003, it is proposed to collaborate with several European colleagues in an international Antarctic Match campaign to obtain detailed, altitude dependent, ozone loss rate measurements for comparisons with chemical transport models and photochemical box models. In addition, the polar stratospheric cloud (PSC) observations will be continued to address questions related to the nucleation of nitric acid hydrates, the existence of large particles within Antarctic PSCs and their role in denitrification, and the index of refraction of PSC particles. The instruments on the balloons will provide high-resolution trajectory measurements, which can be used to assess the accuracy of air parcel temperature histories. This information, coupled with in situ aerosol profile measurements and a microphysical model, will be used to test various PSC nucleation hypotheses, which have direct implications for chlorine activation and denitrification. The instrument will be developed with support from a Major Research Infrastructure instrument development award from NSF.