The Siberian Arctic is warming fast: permafrost is thawing, river chemistry is changing, and coastal ecosystems are affected. We want to understand changes to the Lena River, a major Arctic river flowing to the Arctic Ocean, by collecting 4.5 years of detailed water data, including temperature and carbon and nutrient contents. This dataset records current conditions and helps us to detect future changes. Explore it at https://doi.org/10.1594/PANGAEA.913197 and https://lena-monitoring.awi.de/.

The spectral electrical signal of ice exhibits a strong characteristic behaviour in the frequency range from 100 Hz to 100 kHz, due to polarization effects. With our geophysical method, we can analyse this characteristic to detect subsurface ice. Moreover, we use a model to quantify 2-D ground ice content based on our data. The potential of our new measurement device is showed up. Data were taken on a permafrost site in Yakutia, and the results are in agreement with other existing field data.

The streamflow of Arctic rivers is changing. We analyzed available data (22 gauges, 1936–2015) in the basins of the Yana and Indigirka rivers completely located within the continuous permafrost zone. The results show that the main factor of increasing low flows is the shift from snow to rain due to warming. Other factors related to the release of water from permafrost, glaciers, or aufeis may fractionally contribute to streamflow increase but cannot be quantified based on available data.

Aufeis is formed through a complex interconnection between river water and groundwater. The dynamics of aufeis assessed by the analysis of remote sensing data can be viewed as an indicator of groundwater changes in warming climate which are otherwise difficult to be observed naturally in remote arctic areas. The spatial geodatabase developed shows that aufeis formation conditions may have changed between the mid-20th century and the present in the Indigirka River basin.

This article describes the dataset of the Kolyma Water-Balance Station located at the upstreams of the Kolyma River (Russia). The dataset combines continuous long-term (1948–1997) observations of water balance, hydrological processes, and permafrost. It allows for study of permafrost hydrology interaction processes in a practically unexplored region. We highlight the main historical stages of the station's existence and its scientific significance, and outline the prospects for its future.