Observation of an unusual mid-stratospheric aerosol layer in the Arctic: possible sources and implications for polar vortex dynamics
Observation of an unusual mid-stratospheric aerosol layer in the Arctic: possible sources and implications for polar vortex dynamics
复制标题
北极异常中平流层气溶胶层的观测：极涡动力学的可能来源和影响
DOI：
10.5194/angeo-21-1057-2003
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发表时间：
2003
影响因子：
1.9
通讯作者：
J. Fiedler
中科院分区：
文献类型：
--
作者：
M. Gerding;G. Baumgarten;U. Blum;J. Thayer;K. Fricke;R. Neuber;J. Fiedler
到2000/2001年冬季初，四个不同的北极激光雷达站探测到了一个神秘的平流层气溶胶层。首先于2000年11月16日在格陵兰Sondre Stromfjord附近（北纬67度，西经51度）约38公里的高度观测到气溶胶层，并于2000年11月19日在挪威Andenes附近（北纬69度，西经16度）观测到气溶胶层。随后，在2000年12月初，在瑞典的基律纳（北纬68度，东经21度）和斯匹次卑尔根岛的Ny-Alesund（北纬79度，东经12度）附近观测到气溶胶层。没有中纬度激光雷达站观测到在这一高度区域存在气溶胶。这一层在2000/2001年整个冬季持续存在，至少持续到2001年2月12日。2000年11月，在532 nm波长处的后向散射比高达1.1，半高宽约为2.5 km。到2001年2月初，该层已从38公里的高度沉降到约26公里。ALOMAR和Koldewey激光雷达在几个波长下的测量表明，颗粒大小在30至50 nm之间。去偏振测量显示，该层中的颗粒是非球面的，因此是固体。在平流层中部，周围大气温度太高，不足以支持由冰或酸水溶液组成的云粒子的原位形成或存在。此外，2000年没有火山爆发，火山爆发可能会将气溶胶注入平流层上部。因此，本文将讨论气溶胶的其他来源，如流星体碎片、凝聚的火箭燃料或在带电太阳粒子影响下产生的气溶胶。轨迹计算说明了极地涡旋内的气溶胶云的路径，并用于连接在不同的激光雷达站点的观测。根据层的下降速率和粒子沉降速率，估计极涡内35至30公里处的平均向下运动速度约为124米/天，在极涡边缘的数值更高。关键词。大气成分和结构（气溶胶和粒子;中层大气成分和化学）-气象学和大气动力学（中层大气动力学）
By the beginning of winter 2000/2001, a mysterious stratospheric aerosol layer had been detected by four different Arctic lidar stations. The aerosol layer was observed first on 16 November 2000, at an altitude of about 38 km near Sondre Stromfjord, Greenland (67° N, 51° W) and on 19 November 2000, near Andenes, Norway (69° N, 16° E). Subsequently, in early December 2000, the aerosol layer was observed near Kiruna, Sweden (68° N, 21° E) and Ny-Alesund, Spitsbergen (79° N, 12° E). No mid-latitude lidar station observed the presence of aerosols in this altitude region. The layer persisted throughout the winter 2000/2001, at least up to 12 February 2001. In November 2000, the backscatter ratio at a wavelength of 532 nm was up to 1.1, with a FWHM of about 2.5 km. By early February 2001, the layer had sedimented from an altitude of 38 km to about 26 km. Measurements at several wavelengths by the ALOMAR and Koldewey lidars indicate the particle size was between 30 and 50 nm. Depolarisation measurements reveal that the particles in the layer are aspherical, hence solid. In the mid-stratosphere, the ambient atmospheric temperature was too high to support in situ formation or existence of cloud particles consisting of ice or an acid-water solution. Furthermore, in the year 2000 there was no volcanic eruption, which could have injected aerosols into the upper stratosphere. Therefore, other origins of the aerosol, such as meteoroid debris, condensed rocket fuel, or aerosols produced under the influence of charged solar particles, will be discussed in the paper. Trajectory calculations illustrate the path of the aerosol cloud within the polar vortex and are used to link the observations at the different lidar sites. From the descent rate of the layer and particle sedimentation rates, the mean down-ward motion of air within the polar vortex was estimated to be about 124 m/d between 35 and 30 km, with higher values at the edge of the vortex. Key words. Atmospheric composition and structure (aerosols and particles; middle atmosphere composition and chemistry) – meteorology and atmospheric dynamics (middle atmosphere dynamics)