Chemical signatures of aged Pacific marine air: Mixed layer and free troposphere as measured during PEM‐West A
Chemical signatures of aged Pacific marine air: Mixed layer and free troposphere as measured during PEM‐West A
复制标题
老化太平洋海洋空气的化学特征：PEM-West A 期间测量的混合层和自由对流层
DOI：
10.1029/95jd00410
复制
发表时间：
1996
影响因子：
--
通讯作者：
Y. Kondo
中科院分区：
文献类型：
--
作者：
G. Gregory;A. Bachmeier;D. Blake;B. Heikes;D. Thornton;A. Bandy;J. Bradshaw;Y. Kondo
太平洋是北方半球仅存的几个相对没有直接人为排放的区域之一。然而，空气污染物的远距离迁移正开始对太平洋上空的大气层产生重大影响。1991年9月和10月，美国航天局进行了太平洋探索任务-西A考察，研究大气化学和关键大气痕量物种的本底收支。飞机采样集中在北方太平洋，北纬0°至40°，东经115°至180°。本文总结了相对成熟的太平洋海洋空气（在海洋上空停留时间≥10天）的化学特征。化学特征表明，海洋空气并不总是没有大陆的影响。古老的海洋空气循环周围的半永久性副热带高压位于亚洲大陆的影响，注入大陆空气与人为排放。这种注入是由于亚洲外流在东移冷锋之后从大陆上席卷而来。当与具有更偏南路径的老化海洋空气相比时，这种注入导致许多人为/大陆物种的混合比增强，并且通常是那些在自由对流层中具有数周寿命的物种。增强被认为是短寿命的物种与几天的注入大陆排放量在运输过程中耗尽（约一个星期）周围的半永久性副热带高压的寿命。
The Pacific Ocean is one of the few remaining regions of the northern hemisphere that is relatively free of direct anthropogenic emissions. However, long-range transport of air pollutants is beginning to have a significant impact on the atmosphere over the Pacific. In September and October 1991, NASA conducted the Pacific Exploratory Mission-West A expedition to study the atmospheric chemistry and background budgets of key atmospheric trace species. Aircraft sampling centered on the northern Pacific, 0° to 40°N and 115° to 180°E. The paper summarizes the chemical signature of relatively well-aged Pacific marine air (residence time ≥10 days over the ocean). The chemical signatures show that marine air is not always devoid of continental influences. Aged marine air which circulates around the semipermanent subtropical anticyclone located off the Asian continent is influenced by infusion of continental air with anthropogenic emissions. The infusion occurs as the result of Asian outflow swept off the continent behind eastward moving cold fronts. When compared to aged marine air with a more southerly pathway, this infusion results in enhancements in the mixing ratio of many anthropogenic/continental species and typically those with lifetimes of weeks in the free troposphere. Less enhancement is seen for the short-lived species with lifetimes of a few days as infused continental emissions are depleted during transport (about a week) around the semipermanent subtropical high.