This paper describes GRUAN's strategy to a network-wide change in the operational radiosonde, from Vaisala RS92 to RS41. GRUAN's main goal is providing long-term data records that are free of inhomogeneities due to instrumental effects, which requires proper change management. The approach is to fully characterize the differences between both radiosonde types, using a.o. laboratory tests, twin soundings, ancillary data, and by drawing from the various fields of expertise available in GRUAN.

This paper developed a drilling trajectory measuring instrumentation (DTMI) based on the interference fiber optic gyro (FOG), which can work continuously, for 4 hours, in an environment where the ambient temperature does not exceed 270 °C and the pressure does not exceed 120 MPa in ultra-deep borehole. The DTMI has the characteristic of anti-electromagnetic interference, therefore，this DTMI has great potential in the promotion and development of geological drilling technology.

We report the results from the deployment of a newly developed in situ sensor for dissolved gases measurements. Its adaptation to high gas concentrations and dissolved gas pressures was proven. The campaign leads to a first continuous profile of methane on the first 150 m, and allowed to compare the data with previous measurements. The fast response of the instrument makes this technique a good candidate for regular monitoring of those type of lakes, for anticipating disastrous gas eruptions.