A global historical radiosondes and tracked balloons archive on standard pressure levels back to the 1920s

The Comprehensive Historical Upper-Air Network (CHUAN version 1.7), which was substantially extended in 2013, and the Integrated Global Radiosonde Archive (IGRA) are the most important collections of upper-air measurements taken before 1958. CHUAN (tracked) balloon data start in 1900, with higher numbers from the late 1920s onward, whereas IGRA data start in 1937. However, a substantial fraction of those measurements have not been taken at synoptic times (preferably 00:00 or 12:00 GMT) and on altitude levels instead of standard pressure levels. To make them comparable with more recent data, the records have been brought to synoptic times and standard pressure levels using state-of-the-art interpolation techniques, employing geopotential information from the National Oceanic and Atmospheric Administration (NOAA) 20th Century Reanalysis (NOAA 20CR). From 1958 onward the European Re-Analysis archives (ERA-40 and ERA-Interim) available at the European Centre for Medium-Range Weather Forecasts (ECMWF) are the main data sources. These are easier to use, but pilot data still have to be interpolated to standard pressure levels. Fractions of the same records distributed over different archives have been merged, if necessary, taking care that the data remain traceable back to their original sources. If possible, station IDs assigned by the World Meteorological Organization (WMO) have been allocated to the station records. For some records which have never been identified by a WMO ID, a local ID above 100 000 has been assigned. The merged data set contains 37 wind records longer than 70 years and 139 temperature records longer than 60 years. It can be seen as a useful basis for further data processing steps, most notably homogenization and gridding, after which it should be a valuable resource for climatological studies. Homogeneity adjustments for wind using the NOAA-20CR as a reference are described in Ramella Pralungo and Haimberger (2014). Reliable homogeneity adjustments for temperature beyond 1958 using a surface-data-only reanalysis such as NOAA-20CR as a reference have yet to be created.

综合历史高空观测网（Comprehensive Historical Upper-Air Network，CHUAN 1.7版）与全球无线电探空仪综合档案库（Integrated Global Radiosonde Archive，IGRA）是1958年前最重要的高空观测数据集，其中CHUAN于2013年完成了大幅扩充。CHUAN（探空追踪）探空气球观测数据起始于1900年，1920年代末之后数据量显著提升；而IGRA数据则始于1937年。然而，上述观测数据中有相当一部分并非采集于标准天气观测时次（优选格林尼治标准时间00:00或12:00），且采用海拔高度层级而非标准气压层级进行记录。为使其可与近年数据进行比对，研究人员借助美国国家海洋和大气管理局（National Oceanic and Atmospheric Administration，NOAA）20世纪再分析资料（NOAA 20CR）的位势信息，采用当前领先的插值技术，将所有记录统一至标准天气观测时次与标准气压层级。1958年之后，欧洲中期天气预报中心（European Centre for Medium-Range Weather Forecasts，ECMWF）提供的欧洲再分析档案（ERA-40与ERA-Interim）成为主要数据源。这类数据更易于使用，但仍需将测风气球观测数据插值至标准气压层级。对于分散在不同档案中的同一记录片段，必要时会进行合并，并确保数据可追溯至原始来源。若可行，会为观测站记录分配世界气象组织（World Meteorological Organization，WMO）指定的气象站站号；对于部分从未被分配WMO站号的记录，则会分配100000以上的本地站号。合并后的数据集包含37条时长超过70年的风场观测记录，以及139条时长超过60年的温度场观测记录。该数据集可作为后续数据处理步骤（尤其是均一化处理与网格化处理）的实用基础，完成上述处理后，它将成为气候学研究的宝贵资源。针对风场的均一化调整（以NOAA-20CR为参考基准）已在Ramella Pralungo与Haimberger（2014）的研究中进行了阐述。而针对1958年之后的温度场，仅以地表数据再分析资料（如NOAA-20CR）作为参考基准的可靠均一化调整方法仍有待研发。