The implications of Vaisala's new Radiosonde RS41 on improved in-situ observations for meteorological applications

With radiosondes temperature, humidity, pressure, wind, vertical and horizontal location can be measured in-situ up to 35 kilometers. Accurate in-situ observations provide value for many meteorological applications.

Vaisala has developed a new generation of products that support these needs and requirements as they relate to sounding observations, namely Vaisala Radiosonde RS41 and Vaisala DigiCORA® Sounding System MW41. These 4th generation sounding products bring new possibilities for all categories of users (e.g., data providers, forecasters, researchers).

The Vaisala Radiosonde RS41 introduces an improved level of in-situ observation accuracy and quality. RS41 sensor technologies and state-of-art design and manufacturing methodologies, combined with extreme ease of use, ensure reliable and highly accurate atmospheric observations. For instance, a new humidity measurement concept allows for improvements to humidity data, which is important since precise humidity values are challenging to obtain remotely. In addition, a new temperature sensor delivers consistent and accurate measurements throughout the profile.

A Global Positioning System (GPS) based measurement principle is used for calculating atmospheric pressure in the RS41-SG radiosonde. GPS-based pressure measurement provides a high-quality end result that is suitable for most soundings data applications. An accurate pressure sensor can provide value, for example, in applications where observations of non-hydrostatic pressure profiles are required, in situations where the highest obtainable measurement accuracy within the lowest kilometers of flight brings benefits or in climatological data series which can benefit from continuation of direct pressure measurement principle. With RS41 radiosonde, there will be also a model available with a pressure sensor.

RS41 calibration references are traceable to International System of Units (SI units). Unbroken metrological traceability chain to internationally recognized measurement standards combined with defined measurement accuracy over the measurement range provides the basis for good performance. Anchoring of the measurement result to a known reference provides an increased level of confidence for end users in terms of measurement accuracy and quality. The RS41 radiosonde performance has been well-characterized and thoroughly tested in both laboratory and environmental settings.

Good sounding observations are dependent on a high-quality, optimized soundings process. It has been recognized that ease of use is a key factor in the soundings process, as it can reduce the potential for human error, enabling consistent and quality observations. To address ease of use considerations, user centric design methodologies have been used extensively during 4th generation offering development. In total 17 end-users from 11 sounding stations in 5 countries have contributed to the evaluation and design.

In summary, a 4th generation sounding system, consisting of Vaisala Radiosonde RS41 and DigiCORA® Sounding System MW41, will be discussed, with an emphasis on the data retrieval process, improvements in data quality, and the implications for end-users responsible for contributing to the assessment and prediction of the atmosphere and its evolution.