A Study of Technique for the Measurement of Total Reactive Nitrogen in the Troposphere

NO_y的测量是通过在加入CO的条件下，在加热的金管表面上催化转化为NO来进行的。随后，如上所述，用NO检测器检测该NO。为了确定NO和NO_y仪器的零水平，将不含NO或NO_y的纯化气体引入反应室，而不是环境空气。结果表明，纯净空气比纯净氧和纯净氮更能满足稳定和低零信号的要求。NO_y仪器性能的一个重要标准是它能将加热金管上的活性氮转化为NO。为了解释1992年1月在瑞典北方的一次气球飞行中获得的数据，关键是要知道NO_y在多大程度上是由活性氮转化为NO的。实验室测量表明，转换效率接近100%，并在实验室进行了大量的测量，以研究样品空气中冷凝水的可能影响。在自由对流层，温度通常远低于0摄氏度。这些低温导致NO_y仪器的入口管线冷却。下降的飞机在对流层低层和边界层遇到更多的湿空气，这些湿空气会在冷却的样品线上凝结。考虑到这一影响，对NO_y仪器进行了改进，以防止在今后的现场测量中出现这种干扰。

NO_y is measured by converting it to NO catalytically on the surface of a heated gold tube under the addition of CO. Subsequently this NO is detected with an NO detector as described above.To determine the zero level of NO and NO_y instruments purified gas that doesn't contain NO or NO_y is directed into the reaction chamber instead of the ambient air. It was shown that purified air fulfills therequirements for stable and low zero signal better than purified oxygen and nitrogen.One important criterion for the performance of the NO_y instrument is it's capability to convert reactive nitrogen on the heated gold tube into NO. For the interpretation of the data obtained during a balloonflight in Northern Sweden in January 92 it was crucial to know to which degree NO_y was converted into NO. Measurements in the laboratory have shown that the conversion efficiency was close to 100%.Extensive measurements in the laboratory have been carried out to study the possible influence of condenced water in the sample air. In the free troposphere the temperatures are usually far below 0ﾟC. These low temperatures cause a cooling of the inlet line of the NO_y instrument. The descending aircraft encountered more humid air in the lower troposphere and boundary layer, which then whould condense on the cooled sample line. Considering this effect modifications of the NO_y instrument were made to prevent this interference in future field measurements.