Polar | University of Wyoming Stratospheric Aerosol Measurements

The globally distributed stratospheric aerosol are a constant but highly variable component of the Earth’s atmosphere. They impact climate through their albedo and ozone through heterogeneous chemistry. For these reasons they must be considered in all climate prediction models, and there are a host of measurement platforms to characterize these aerosol. Their optical properties have been measured from satellites, since the late 1970s, while surface based lidar measurements have been completed regularly at a handful of locations since the mid 1970s. The first measurements, however, were completed using in situ instruments deployed on balloons and aircraft in the 1960s. In contrast to the satellite and lidar measurements which provide extinction or backscatter, the in situ measurements provide size distributions, and thus the only direct path for deriving the microphysical parameters required by the global models such as aerosol surface area, volume, and cross section. The longest continuous record of in situ stratospheric aerosol measurements has been completed at Laramie, Wyoming, 1971-2020, comprising nearly 400 individual balloon flights. The measurements from these flights since 1989 are contained in this digital archive. In addition to the flights from Laramie there are over 100 flights from McMurdo Station, Antarctica, 45 flights from Kiruna, Sweden, and a handful of flights from 13 other locations throughout the world stretching from 45˚S to 68˚N. The measurements from Laramie from 1971 – 1988 are available on the data base of the Network for the Detection of Atmospheric Composition Change, https://www.ndaccdemo.org/. This record includes the following <strong>Polar </strong>datasets: /Aerosol_InSitu_Meas/SE_Andoya_69N_16E_1996_1997/ /Aerosol_InSitu_Meas/SE_Kiruna_68N_21E_1990-2004/ /Lagrangian measurements South of 60S_2010 /Aerosol_InSitu_Meas/Ant_McMurdo_78S_167E_1989-2010/ Within each of these directories are the following subdirectories/folders: Nr_Full_Profile - Sounding files for aerosol size and number concentration. The file name, e.g. 20080622_WY_WOPC_ATA6m.ASC, indicates the date (yyyymmdd) and location, MM=McMurdo, WY=Laramie, the instrument name (e.g. WOPC_ATA6m). The file extension indicates the vertical resolution, .ASC, implies full data , or an average, e.g. .500m for a 500 m average. These differences in the vertical averaging are separated into separate subfolders. The files include measurements from the surface to balloon burst. All files include general and specific metadata. For the Laramie measurements, where three different instruments (Dust, WOPC, WLPC) have been used, the measurements are further divided into instrument folders. SizeDist_Stratosphere - Lognormal size distributions (either unimodal or bimodal) at the vertical resolution indicated in the file name. The file names are somewhat long and include the name of the source file for the measurements, including the vertical resolution, the altitude at which the size distributions begin (typically the tropopause), and "_Srs_ce" which indicates the fit was completed with the new fitting algorithm which accounts for the instrument counting efficiency at each channel size. All files include general and specific metadata. For the Laramie measurements, where three different instruments (Dust, WOPC, WLPC) have been used, the measurements are further divided into instrument folders. IDL.SAV files are included in each folder for the Antarctic and Kiruna measurements. Some folders contain post script files for quick looks at the data.

全球分布的平流层气溶胶是地球大气中一类恒定却高度可变的组分。它们通过反照率（albedo）影响气候，通过非均相化学反应（heterogeneous chemistry）影响臭氧水平。鉴于此，所有气候预测模型都必须将其纳入考量，目前也已有众多测量平台用于表征这类气溶胶的特性。

自20世纪70年代末起，科研人员已通过卫星对其光学特性开展测量；而自70年代中期以来，少数站点已定期开展地基激光雷达（lidar）测量。不过最早的气溶胶测量工作始于20世纪60年代，当时采用搭载在气球与飞机上的原位（in situ）仪器完成。

与卫星和激光雷达测量所获取的消光（extinction）或后向散射（backscatter）数据不同，原位测量可直接获得气溶胶的粒径分布，因此是推导全球模型所需微物理参数——如气溶胶表面积、体积与截面积——的唯一直接途径。

位于美国怀俄明州拉勒米（Laramie, Wyoming）的观测站拥有1971年至2020年的最长连续平流层气溶胶原位测量记录，累计包含近400次独立气球探测飞行。1989年以来的该站点探测数据已收录至本数字档案。

除拉勒米站点外，本档案还涵盖来自南极麦克默多站（McMurdo Station）的100余次探测飞行、瑞典基律纳（Kiruna）的45次探测飞行，以及全球其他13个站点的少量探测数据，观测范围覆盖南纬45°至北纬68°。1971年至1988年的拉勒米测量数据可从大气成分变化探测网络（Network for the Detection of Atmospheric Composition Change, NDACC）的数据库获取，网址为https://www.ndaccdemo.org/。

本记录包含以下极地数据集：
/Aerosol_InSitu_Meas/SE_Andoya_69N_16E_1996_1997/
/Aerosol_InSitu_Meas/SE_Kiruna_68N_21E_1990-2004/
/Lagrangian measurements South of 60S_2010
/Aerosol_InSitu_Meas/Ant_McMurdo_78S_167E_1989-2010/

在上述每个目录下，均包含以下子目录/文件夹：
1. Nr_Full_Profile：用于存储气溶胶粒径与数浓度的探空文件。文件名示例为20080622_WY_WOPC_ATA6m.ASC，其中日期格式为yyyymmdd，地点代码分别为MM（麦克默多）、WY（拉勒米），仪器名称如WOPC_ATA6m。文件扩展名代表垂直分辨率：.ASC表示完整原始数据，带数字后缀的扩展名（如.500m）代表对应米数的平均数据。垂直平均的差异被划分至不同的子文件夹中。所有文件的测量范围均覆盖从地表至气球爆裂高度，且均包含通用元数据（metadata）与专用元数据。针对拉勒米站点的测量数据，由于曾使用Dust、WOPC、WLPC三种不同仪器，数据会进一步按仪器文件夹分类存储。
2. SizeDist_Stratosphere：以文件名中指定的垂直分辨率存储的对数正态粒径分布（lognormal size distributions），包含单峰或双峰两种形式。文件名较长，包含测量源文件名称、垂直分辨率、粒径分布起始高度（通常为对流层顶（tropopause）），以及后缀“_Srs_ce”，该后缀表示拟合过程采用了新算法，可适配各通道粒径下的仪器计数效率。所有文件均包含通用元数据与专用元数据。针对拉勒米站点的测量数据，同样按三种仪器划分子文件夹存储。

南极与基律纳站点的测量数据的每个文件夹中均包含IDL.SAV格式文件。部分文件夹还附带PostScript格式文件，用于快速预览数据。