This paper describes the Global Climate Observing System (GCOS) Reference Upper-Air Network (GRUAN) approach to managing the transition from the Vaisala RS92 to the Vaisala RS41 as the operational radiosonde. The goal of GRUAN is to provide long-term high-quality reference observations of upper-air essential climate variables (ECVs) such as temperature and water vapor. With GRUAN data being used for climate monitoring, it is vital that the change of measurement system does not introduce inhomogeneities to the data record. The majority of the 27 GRUAN sites were launching the RS92 as their operational radiosonde, and following the end of production of the RS92 in the last quarter of 2017, most of these sites have now switched to the RS41. Such a large-scale change in instrumentation is unprecedented in the history of GRUAN and poses a challenge for the network. Several measurement programs have been initiated to characterize differences in biases, uncertainties, and noise between the two radiosonde types. These include laboratory characterization of measurement errors, extensive twin sounding studies with RS92 and RS41 on the same balloon, and comparison with ancillary data. This integrated approach is commensurate with the GRUAN principles of traceability and deliberate redundancy. A 2-year period of regular twin soundings is recommended, and for sites that are not able to implement this, burden-sharing is employed such that measurements at a certain site are considered representative of other sites with similar climatological characteristics. All data relevant to the RS92–RS41 transition are archived in a database that will be accessible to the scientific community for external scrutiny. Furthermore, the knowledge and experience gained regarding GRUAN's RS92–RS41 transition will be extensively documented to ensure traceability of the process. This documentation will benefit other networks in managing changes in their operational radiosonde systems. Preliminary analysis of the laboratory experiments indicates that the manufacturer's calibration of the RS41 temperature and humidity sensors is more accurate than for the RS92, with uncertainties of <0.2 K for the temperature and <1.5 % RH (RH: relative humidity) for the humidity sensor. A first analysis of 224 RS92–RS41 twin soundings at Lindenberg Observatory shows nighttime temperature differences <0.1 K between the Vaisala-processed temperature data for the RS41 (T_RS41) and the GRUAN data product for the RS92 (T_RS92-GDP.2). However, daytime temperature differences in the stratosphere increase steadily with altitude, with T_RS92-GDP.2 up to 0.6 K higher than T_RS41 at 35 km. RH_RS41 values are up to 8 % higher, which is consistent with the analysis of satellite–radiosonde collocations.

中文翻译：

---

在全球气候观测系统参考高空网络（GRUAN）中管理从维萨拉RS92到RS41无线电探空仪的过渡：进度报告

本文介绍了全球气候观测系统（GCOS）参考高空网络（GRUAN）的方法，以管理从维萨拉RS92到维萨拉RS41的运行无线电探空仪的过渡。GRUAN的目标是对高空基本气候变量（ECV）（例如温度和水蒸气）提供长期的高质量参考观测结果。由于将GRUAN数据用于气候监测，因此至关重要的是，测量系统的变化不会在数据记录中引入不均匀性。27个GRUAN站点中的大多数都将RS92作为其运行无线电探空仪发射，并且在2017年最后一个季度RS92的生产结束后，这些站点中的大多数现在已切换到RS41。如此大规模的仪器更改在GRUAN的历史上是前所未有的，并且对网络构成了挑战。已经启动了一些测量程序来表征两种无线电探空仪之间的偏差，不确定性和噪声的差异。这些措施包括实验室测量误差的表征，在同一个气球上使用RS92和RS41进行广泛的双声探测研究以及与辅助数据进行比较。这种集成方法与GRUAN的可追溯性和故意冗余原则相称。建议定期进行两次测深，对于不能执行此操作的站点，应分担负担，以便将某个站点的测量结果视为具有类似气候特征的其他站点的代表。与RS92→RS41转换有关的所有数据都存储在一个数据库中，科学界可以进行外部审查。此外，将广泛记录有关GRUAN的RS92→RS41过渡所获得的知识和经验，以确保过程的可追溯性。这个文件将使其他网络在管理其运行的无线电探空仪系统中受益。实验室实验的初步分析表明，制造商对RS41温度和湿度传感器的校准比RS92更准确，不确定度<0.2？K为温度，湿度传感器为<1.5 %% RH（RH：相对湿度）。对Lindenberg天文台的224个RS92？RS41孪生探测的首次分析显示，夜间温度差异<0.1 ° K在RS41（T _RS41）的Vaisala处理温度数据与RS92的GRUAN数据乘积之间（T _RS92-GDP.2）。但是，平流层中的白天温度差异随海拔高度稳定增加，T _{RS92- GDP.2}在35千米处比T _RS41高 0.6ΔK。RH _RS41值最高可提高8％，这与对卫星无线电探空仪搭配的分析是一致的。