Noctilucent clouds above ALOMAR between 1997 and 2001: Occurrence and properties
Noctilucent clouds above ALOMAR between 1997 and 2001: Occurrence and properties
复制标题
1997 年至 2001 年间 ALOMAR 上空的夜光云：发生情况和性质
DOI：
--
复制
发表时间：
2003
期刊：
影响因子：
--
通讯作者：
G. Cossart
中科院分区：
文献类型：
--
作者：
J. Fiedler;G. Baumgarten;G. Cossart
[1]我们报告了位于挪威北方69°N，16°E的地基激光雷达对平流层云（NLC）的观测结果。ALOMAR瑞利/米氏/拉曼（RMR）激光雷达进行测量北极中层大气从1997年至2001年期间每年6月1日至8月15日。该数据集包含1122小时的激光雷达观测，其中408小时包括NLC特征。NLC发生频率的年际变化表现为强NLC减少，而弱NLC发生频率增加。NLC发生的季节变化显示了一个非常明显的核心时期，NLC出现在43%的时间。NLC的基本性质由三个参数表征：体后向散射系数的最大值βmax（亮度）、质心高度zc和半宽δz（厚度）。一个典型的在ALOMAR之上的NLC在5年的时间里拥有亮度βmax = 9.6 × 10−10 m−1 sr−1，高度zc = 83.3 km，厚度δz = 1.2 km。这些参数的年际变化表现为亮度减小、高度增加和厚度基本不变，而季节变化高于这些年际变化。在核心时段，NLC明显比赛季初和赛季末更亮。NLCs的高度和厚度在季节性下降。
[1] We report on observations of noctilucent clouds (NLCs) by a ground-based lidar located in northern Norway at 69°N, 16°E. The ALOMAR Rayleigh/Mie/Raman (RMR) lidar conducted measurements of the Arctic middle atmosphere from 1 June to 15 August during each year from 1997 to 2001. This data set contains 1122 hours of lidar observations whereof 408 hours include NLC signatures. The interannual variation of the NLC occurrence frequency shows a decrease of strong NLCs, while weak NLCs occur more frequent. The seasonal variation of the NLC occurrence shows a well pronounced core period where NLCs appeared during 43% of the time. The basic properties of NLCs are characterized by three parameters: maximum value of the volume backscatter coefficient βmax (≡brightness), centroid altitude zc, and half width δz (≡thickness). A typical NLC above ALOMAR during the 5-year period reported here owns a brightness of βmax = 9.6 × 10−10 m−1 sr−1, an altitude of zc = 83.3 km, and a thickness of δz = 1.2 km. The interannual variation of the parameters shows a decrease of the brightness, an increase of the altitude, and a nearly constant thickness, while seasonal variability is higher than these interannual changes. During the core period, the NLCs are noticeably brighter than at the beginning as well as the end of the season. Altitude and thickness of NLCs decrease during the season.