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年之前继续利用气球对南极上空的臭氧进行实地观测。由于大量的含氯氟烃进入大气层，南极平流层中的臭氧现在的季节循环与过去大不相同。在过去，南极的臭氧量主要受全球环流过程的控制，导致冬季臭氧的积累。今天，氯的存在加上寒冷的温度，造成平流层云，导致春季臭氧最低值，这是由于臭氧和氯之间的催化反应在云颗粒表面被激活。导致这种臭氧损失的机制一直是许多科学活动的主题，并取得了重大进展;然而，仍然存在一些悬而未决的问题，需要从麦默多站进行更多的臭氧和平流层粒子剖面测量。在南春期间大约每三天完成一次臭氧剖面测量，这将有助于为平流层最大氯负荷期间的观测奠定基础。这将有助于建立必要的测量基础，以便在今后十年内随着平流层氯的减少而观察臭氧恢复的初步迹象。对臭氧垂直分布的测量将是用来观察平流层氯含量下降后随高度而恢复的最初迹象的重要工具之一。2003年，拟与若干欧洲同事合作开展一项国际南极匹配运动，以获得详细的、取决于海拔高度的臭氧损失率测量数据，用于与化学迁移模型和光化学箱模型进行比较。此外，还将继续进行极地平流层云观测，以解决与硝酸水合物成核、南极平流层云内是否存在大颗粒及其在脱氮中的作用以及平流层云颗粒折射率有关的问题。气球上的仪器将提供高分辨率的轨迹测量，可用于评估气团温度历史的准确性。这些信息，再加上在现场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，这对氯活化和反硝化有直接的影响。该仪器将在NSF主要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.