Mechanisms leading to the 2016 giant twin glacier collapses, Aru Range, Tibet The Cryosphere DOI 10.5194/tc-12-2883-2018 7 September 2018 In Tibet, two glaciers suddenly collapsed in summer 2016 and produced two gigantic ice avalanches, killing nine people. This kind of phenomenon is extremely rare. By combining a detailed modelling study and high-resolution satellite observations, we show that the event was triggered by an increasing meltwater supply in the fine-grained material underneath the two glaciers. Contrary to what is often thought, this event is not linked to a change in the thermal condition at the glacier base. Read more
Integrated management of a Swiss cropland is not sufficient to preserve its soil carbon pool in the long term Biogeosciences DOI 10.5194/bg-15-5377-2018 6 September 2018 It is of great interest to know whether croplands act as a net source or sink of atmospheric CO2and if soil carbon © stocks are preserved over long timescales due to the role of C in soil fertility. For a cropland in Switzerland it was found that managing the field under the Swiss framework of the Proof of Ecological Performance (PEP) resulted in soil C losses of 18.0 %. Additional efforts are needed to bring Swiss management practices closer to the goal of preserving soil C in the long term. Read more
Technical note: Two types of absolute dynamic ocean topography Ocean Science DOI 10.5194/os-14-947-2018 4 September 2018 Two types of marine geoid exist with the first type being the average level of sea surface height if the water is at rest (classical definition), and the second type being satellite-determined with the condition that the water is usually not at rest. The associated absolute dynamic ocean topography (DOT) also has two types. Horizontal gradients of the two DOTs are different with the 1st (2nd) type representing the absolute (relative) surface geostrophic currents. Read more
Radiative feedbacks of dust in snow over eastern Asia in CAM4-BAM Atmospheric Chemistry and Physics DOI 10.5194/acp-18-12683-2018 31 August 2018 This study extends our previous investigation in dust–radiation interactions to investigate SRF and its feedbacks on the regional climate and the dust cycle over east Asia by use of the CAM4-BAM. Our results show that SRF increases the east Asian dust emissions significantly by 13.7 % in the spring, in contrast to −7.6 % of decreased dust emissions by DRF. Hence, a significant feature of SRF on the Tibetan Plateau can create a positive feedback loop to enhance the dust cycle over east Asia. Read more
Promising Oldest Ice sites in East Antarctica based on thermodynamical modelling The Cryosphere DOI 10.5194/tc-12-2773-2018 30 August 2018 Our paper provides an important review of the state of knowledge for oldest-ice prospection, but also adds new basal geothermal heat flux constraints from recently acquired high-definition radar data sets. This is the first paper to contrast the two primary target regions for oldest ice: Dome C and Dome Fuji. Moreover, we provide statistical comparisons of all available data sets and a summary of the community’s criteria for the retrieval of interpretable oldest ice since the 2013 effort. Read more
The Variable Infiltration Capacity model version 5 (VIC-5): infrastructure improvements for new applications and reproducibility Geoscientific Model Development DOI 10.5194/gmd-11-3481-2018 30 August 2018 Variable Infiltration Capacity (VIC) is a widely used hydrologic model. This paper documents the development of VIC version 5, which includes a reconfiguration of the model source code to support a wider range of modeling applications. It also represents a significant step forward for the VIC user community in terms of support for a range of modeling applications, reproducibility, and scientific robustness. Read more
Varying soil moisture–atmosphere feedbacks explain divergent temperature extremes and precipitation projections in central Europe Earth System Dynamics DOI 10.5194/esd-9-1107-2018 30 August 2018 Climate change projections of temperature extremes are particularly uncertain in central Europe. We demonstrate that varying soil moisture–atmosphere feedbacks in current climate models leads to an enhancement of model differences; thus, they can explain the large uncertainties in extreme temperature projections. Using an observation-based constraint, we show that the strong drying and large increase in temperatures exhibited by models on the hottest day in central Europe are highly unlikely. Read more
The point of no return for climate action: effects of climate uncertainty and risk tolerance Earth System Dynamics DOI 10.5194/esd-9-1085-2018 30 August 2018 We determine the point of no return (PNR) for climate change, which is the latest year to take action to reduce greenhouse gases to stay, with a certain probability, within thresholds set by the Paris Agreement. For a 67 % probability and a 2 K threshold, the PNR is the year 2035 when the share of renewable energy rises by 2 % per year. We show the impact on the PNR of the speed by which emissions are cut, the risk tolerance, climate uncertainties and the potential for negative emissions. Read more
Sporadic auroras near the geomagnetic equator: in the Philippines, on 27 October 1856 Annales Geophysicae DOI 10.5194/angeo-36-1153-2018 29 August 2018 A record has been found of an “aurora” observed on 27 October 1856 in the Philippines, practically at the magnetic equator. An analysis of this report indicates that it could belong to a “sporadic aurora” because of low magnetic activity at that time. We provide a possible physical mechanism that could explain the appearance of this sporadic, low-latitude aurora, according to the analyses on the observational report and magnetic observations at that time. Read more
Population exposure to droughts in China under the 1.5 ºC global warming target Earth System Dynamics DOI 10.5194/esd-9-1097-2018 29 August 2018 Results show that an additional 6.97 million people will be exposed to droughts in China under a 1.5 ºC target relative to reference period, mostly in the east of China. Demographic change is the primary contributor to exposure. Moderate droughts contribute the most to exposure among 3 grades of drought. Our simulations suggest that drought impact on people will continue to be a large threat to China under the 1.5 ºC target. It will be helpful in guiding adaptation and mitigation strategies. Read more