New Last Glacial Maximum ice thickness constraints for the Weddell Sea Embayment, Antarctica The Cryosphere DOI 10.5194/tc-13-2935-2019 22 November 2019 We studied the history of ice masses at three locations in the Weddell Sea Embayment, Antarctica. We measured rare isotopes in material sourced from mountains overlooking the Slessor Glacier, Foundation Ice Stream, and smaller glaciers on the Lassiter Coast. We show that ice masses were between 385 and 800 m thicker during the last glacial cycle than they are at present. The ice masses were both hundreds of metres thicker and remained thicker closer to the present than was previously thought. Read more
Evaluating climate emulation: fundamental impulse testing of simple climate models Earth System Dynamics DOI 10.5194/esd-10-729-2019 22 November 2019 Simple climate models (SCMs) underlie many important scientific and decision-making endeavors. This illustrates the need for their use to be rooted in a clear understanding of their fundamental responses. In this study, we provide a comprehensive assessment of model performance by evaluating the fundamental responses of several SCMs. We find biases in some responses, which have implications for decision science. We conclude by recommending a standard set of validation tests for any SCM. Read more
Melt at grounding line controls observed and future retreat of Smith, Pope, and Kohler glaciers The Cryosphere DOI 10.5194/tc-13-2817-2019 15 November 2019 We used a number of computer simulations to understand the recent retreat of a rapidly changing group of glaciers in West Antarctica. We found that significant melt underneath the floating extensions of the glaciers, driven by relatively warm ocean water at depth, was likely needed to cause the large retreat that has been observed. If melt continues around current rates, retreat is likely to continue through the coming century and extend beyond the present-day drainage area of these glaciers. Read more
The first version of the Pan-European Indoor Radon Map Natural Hazards and Earth System Sciences DOI 10.5194/nhess-19-2451-2019 15 November 2019 The first version of the Pan-European Indoor Radon Map is presented in this article. The map has been developed using summary statistics estimated from 1.2 million samples. It represents an average radon concentration per 10 km x 10 km grid cell under the assumption that there are dwellings in the grid cell. It is a major contribution to the understanding of the exposure to ionizing radiation of Europeans and a first step towards a European radon exposure and, in the future, radon dose map. Read more
Seismic location and tracking of snow avalanches and slush flows on Mt. Fuji, Japan Earth Surface Dynamics DOI 10.5194/esurf-7-989-2019 15 November 2019 Avalanches and slush flows from Mt. Fuji are a major natural hazard as they may attain run-out distances of up to 4 km and destroy parts of the forest and infrastructure. We located and tracked them for the first time using seismic data. Numerical simulations were conducted to assess the precision of the seismic tracking. We also inferred dynamical properties characterizing these hazardous mass movements. This information is indispensable for assessing avalanche risk in the Mt. Fuji region. Read more
Calving cycle of the Brunt Ice Shelf, Antarctica, driven by changes in ice shelf geometry The Cryosphere DOI 10.5194/tc-13-2771-2019 15 November 2019 Two large icebergs are about to break off from the Brunt Ice Shelf in Antarctica. Rifting started several years ago and is now approaching its final phase. Satellite data and computer simulations show that over the past 2 decades, growth of the ice shelf has caused a build-up of forces within the ice, which culminated in its fracture. These natural changes in geometry coincided with large variations in flow speed, a process that is thought to be relevant for all Antarctic ice shelf margins. Read more
Effects of land use and anthropogenic aerosol emissions in the Roman Empire Climate of the Past DOI 10.5194/cp-15-1885-2019 8 November 2019 Using the global aerosol–climate model ECHAM-HAM-SALSA, the effect of humans on European climate in the Roman Empire was quantified. Both land use and novel estimates of anthropogenic aerosol emissions were considered. We conducted simulations with fixed sea-surface temperatures to gain a first impression about the anthropogenic impact. While land use effects induced a regional warming for one of the reconstructions, aerosol emissions led to a cooling associated with aerosol–cloud interactions. Read more
Electron pairing in mirror modes: surpassing the quasi-linear limit Annales Geophysicae DOI 10.5194/angeo-37-971-2019 8 November 2019 The mirror mode starts as a zero-frequency ion fluid instability and saturates quasi-linearly at very low magnetic level, while forming extended magnetic bubbles. These trap the adiabatically bouncing electron component which forms pairs near the mirror points. The large pair anisotropy causes further growth beyond quasilinear level. Including pressure equilibrium gives and estimate of the required pair density. Read more
Microbial community composition and abundance after millennia of submarine permafrost warming Biogeosciences DOI 10.5194/bg-16-3941-2019 8 November 2019 Permafrost temperatures increased substantially at a global scale, potentially altering microbial assemblages involved in carbon mobilization before permafrost thaws. We used Arctic Shelf submarine permafrost as a natural laboratory to investigate the microbial response to long-term permafrost warming. Our work shows that millennia after permafrost warming by > 10 °C, microbial community composition and population size reflect the paleoenvironment rather than a direct effect through warming. Read more
The biophysics, ecology, and biogeochemistry of functionally diverse, vertically and horizontally heterogeneous ecosystems: the Ecosystem Demography model, version 2.2 – Part 1: Model description Geoscientific Model Development DOI 10.5194/gmd-12-4309-2019 8 November 2019 Our paper describes the Ecosystem Demography model. This computer program calculates how plants and ground exchange heat, water, and carbon with the air, and how plants grow, reproduce and die in different climates. Most models simplify forests to an average big tree. We consider that tall, deep-rooted trees get more light and water than small plants, and that some plants can with shade and drought. This diversity helps us to better explain how plants live and interact with the atmosphere. Read more
