Brief communication: New sonde to unravel the mystery of polar subglacial lakes

. The newly developed RECoverable Autonomous Sonde (RECAS) allows sampling and analysis of subglacial water while the subglacial lake remains isolated from the surface. The sonde was successfully tested in East Antarctica during 2021-2022 field season: it reached the ice sheet base at the depth of 200.3 m, sampled melted water from basal ice and recorded the 15 parameters (pressure, temperature, pH, and conductivity) of melted water. Then the sonde returned to the ice surface. The average downward penetration rate was 1.85 m h -1 , and the average upward penetration rate was 2.94 m h -1 .