We report on the observation of a directional anisotropy in the intensity of backscattered light. The measurement was performed using a laser dust logger in the SPC14 drill hole at the geographic South Pole. We find the anisotropy axis to be compatible with the ice flow direction. It is discussed in comparison to a similar anisotropy observed by the IceCube Neutrino Observatory. In future, the measurement principle may provide a continuous record of crystal properties along entire drill holes.

Chile hosts glaciers in a large range of latitudes and climates. To project future ice extent, a sound quantification of the energy exchange between atmosphere and glaciers is needed. We present new data for six Chilean glaciers belonging to three glaciological zones. In the Central Andes, the main energy source for glacier melt is the incoming solar radiation, while in southern Patagonia heat provided by the mild and humid air is also important. Total melt rates are higher in Patagonia.

We used data that we collected on RV Polarstern cruise PS106 in summer 2017 to develop a model for the derivation of melt pond depth on Arctic sea ice from reflectance measurements. We simulated reflectances of melt ponds of varying color and water depth and used the sun zenith angle and the slope of the log-scaled reflectance at 710 nm to derive pond depth. We validated the model on the in situ melt pond data and found it to derive pond depth very accurately.

This study reports that ERA5-Land (ERA5L) soil temperature bias in permafrost regions correlates with the bias in air temperature and with maximum snow height. While global reanalyses are important drivers for permafrost study, ERA5L soil data are not well suited for directly informing permafrost research decision making due to their warm bias in winter. To address this, future soil temperature products in reanalyses will require permafrost-specific alterations to their land surface models.

How to mitigate the melting of most mountainous glaciers is a disturbing issue for scientists and the public. We chose the Muz Taw Glacier of the Sawir Mountains as our study object. We carried out two artificial precipitation experiments on the glacier to study the role of precipitation in mitigating its melting. The average mass loss from the glacier decreased by over 14 %. We also propose a possible mechanism describing the role of precipitation in mitigating the melting of the glaciers.

We combine lake mapping, landscape observations and sediment core analyses to document the evolution of a thermokarst (thaw) lake in the Canadian Arctic over the last millennia. We conclude that temperature is not the only driver of thermokarst development, as the lake likely started to form during a cooler period around 2000 years ago. The lake is now located in frozen layers with an organic carbon content that is an order of magnitude higher than the usually reported values across the Arctic.

A new Sentinel-1 radar-based sea ice classification algorithm is proposed. We show that the readily available ice charts from operational ice services can reduce the amount of manual work in preparation of large amounts of training/testing data and feed highly reliable data to the trainer in an efficient way. Test results showed that the classifier is capable of retrieving three generalized cover types with overall accuracy of 87 % and 67 % in the winter and summer seasons, respectively.

We describe new geologic evidence from Antarctica that demonstrates changes in East Antarctic Ice Sheet (EAIS) extent over the past ~ 15 million years. Our data show that the EAIS was a persistent feature in the Transantarctic Mountains for much of that time, including some (but not all) times when global temperature may have been warmer than today. Overall, our results comprise a long-term record of EAIS change and may provide useful constraints for ice sheet models and sea-level estimates.

The amount of solar energy absorbed by Earth is believed to strongly depend on clouds. Here, we investigate this relationship using satellite data and 32 climate models, showing that this relationship holds everywhere except over polar seas, where an increased reflection by clouds corresponds to an increase in absorbed solar radiation at the surface. This interplay between clouds and sea ice reduces by half the increase of net radiation at the surface that follows the sea ice retreat.

Glacial algal blooms play a significant role in darkening the Greenland Ice Sheet during summertime. The dark pigments generated by glacial algae could substantially reduce the bare ice albedo and thereby enhance surface melt. We used satellite data to map the spatial distribution of glacial algae and characterized the seasonal growth pattern and interannual trends of glacial algae in southwestern Greenland. Our study is important for bridging microbial activities with ice sheet mass balance.

The Antarctic precipitation is evaluated against space radar data in the most recent climate model intercomparison CMIP6 and reanalysis ERA5. The seasonal cycle is mostly well reproduced, but relative errors are higher in areas of complex topography, particularly in the higher-resolution models. At continental and regional scales all results are biased high, with no significant progress in the more recent models. Predicting Antarctic contribution to sea level still requires model improvements.

Greenland's glaciers in contact with the ocean drain the majority of the ice sheet (GrIS). Deep troughs along the shelf branch into fjords, connecting glaciers with ocean waters. The heat from the ocean entering deep troughs may then accelerate the mass loss. Onshore heat transport through troughs was investigated with an ocean model. Processes that drive the delivery of ocean heat respond differently by region to increasing GrIS meltwater, mean circulation, and filtering out of storms.

This study measured energy available for snowmelt during the 2016 and 2017 snow seasons in Kosciuszko National Park, NSW, Australia, and identified common traits for days with similar weather characteristics. The analysis showed that energy available for snowmelt was highest in the days before cold fronts passed through the region due to higher air temperatures. Regardless of differences in daily weather characteristics, solar radiation contributed the highest amount of energy to snowpack melt.