The impact of mineral dust on cloud formation during the Saharan dust event in April 2014 over Europe Atmospheric Chemistry and Physics DOI 10.5194/acp-18-17545-2018 11 December 2018 The impact of desert dust on cloud formation is investigated for a major Saharan dust event over Europe by interactive regional dust modeling. Dust particles are very efficient ice-nucleating particles promoting the formation of ice crystals in clouds. The simulations show that the observed extensive cirrus development was likely related to the above-average dust load. The interactive dust–cloud feedback in the model significantly improves the agreement with aircraft and satellite observations. Read more
ESM-SnowMIP: assessing snow models and quantifying snow-related climate feedbacks Geoscientific Model Development DOI 10.5194/gmd-11-5027-2018 10 December 2018 This paper provides an overview of a coordinated international experiment to determine the strengths and weaknesses in how climate models treat snow. The models will be assessed at point locations using high-quality reference measurements and globally using satellite-derived datasets. How well climate models simulate snow-related processes is important because changing snow cover is an important part of the global climate system and provides an important freshwater resource for human use. ESM-SnowMIP: assessing snow models and quantifying snow-related climate feedbacks">Read more
Hydro-climatic variability in the southwestern Indian Ocean between 6000 and 3000 years ago Climate of the Past DOI 10.5194/cp-14-1881-2018 7 December 2018 The 4.2 ka eventbetween 4.2 and 3.9 ka has been widely discussed in the Northern Hemsiphere but less reported in the Southern Hemisphere. Here, we use speleothem records from Rodrigues in the southwestern Indian Ocean spanning from 6000 to 3000 years ago to investigate the regional hydro-climatic variability. Our records show no evidence for an unusual climate anomaly between 4.2 and 3.9 ka. Instead, it shows a multi-centennial drought between 3.9 and 3.5 ka. Read more
Light absorption by marine cyanobacteria affects tropical climate mean state and variability Earth System Dynamics DOI 10.5194/esd-9-1283-2018 5 December 2018 We use an Earth system model to study the effects of light absorption by marine cyanobacteria on climate. We find that cyanobacteria have a considerable cooling effect on tropical SST with implications for ocean and atmosphere circulation patterns as well as for climate variability. The results indicate the importance of considering phytoplankton light absorption in climate models, and specifically highlight the role of cyanobacteria due to their regulative effect on tropical SST and climate. Read more
Seasonal to decadal variability in ice discharge from the Greenland Ice Sheet The Cryosphere DOI 10.5194/tc-12-3813-2018 3 December 2018 We derive the first continuous record of total ice discharged from all large Greenland outlet glaciers over the 2000–2016 period, resolving a distinct pattern of seasonal variability. We compare these results to glacier retreat and meltwater runoff and find that while runoff has a limited impact on ice discharge in summer, long-term changes in discharge are highly correlated to retreat. These results help to better understand Greenland outlet glacier sensitivity over a range of timescales. Read more
Cold-to-warm flow regime transition in snow avalanches The Cryosphere DOI 10.5194/tc-12-3759-2018 30 November 2018 Snow avalanches show complicated flow behaviour, characterized by several flow regimes which coexist in one avalanche. In this work, we analyse flow regime transitions where a powder snow avalanche transforms into a plug flow avalanche by incorporating warm snow due to entrainment. Prediction of such a transition is very important for hazard mitigation, as the efficiency of protection dams are strongly dependent on the flow regime, and our results should be incorporated into avalanche models. Read more
Solar wind and kinetic heliophysics Annales Geophysicae DOI 10.5194/angeo-36-1607-2018 30 November 2018 This paper originated from the lecture I gave as the Hannes Alfvén medalist at the EGU General Assembly in Vienna in spring 2018. The paper reviews various aspects of modern solar wind physics and elucidates the role Alfvén waves play in solar wind acceleration and turbulence, which prevail in the low corona and inner heliosphere. Our understanding of the solar wind has recently made considerable progress based on remote sensing, in situ measurements, kinetic simulation and fluid modeling. Read more
What can seabirds tell us about the tide? Ocean Science DOI 10.5194/os-14-1483-2018 29 November 2018 This paper describes a feasibility study carried out to determine if information gathered for one discipline could berepurposedto provide insight in another. Data gathered during a study of bird distribution were used to investigate whether these same data could be used to measure tidal current velocities and direction. The paper concludes that there is potential to use GPS-tagged birds asdrifters of opportunityand that interdisciplinary sharing of data can provide additional insight. Read more
Field survey of Typhoon Hato (2017) and a comparison with storm surge modeling in Macau Natural Hazards and Earth System Sciences DOI 10.5194/nhess-18-3167-2018 29 November 2018 Typhoon Hato was one of the most damaging natural disaster events in the western Pacific region in 2017. It caused the the worst flooding in Macau since its instrumental records began in 1925. We present a high-resolution survey map recording inundation depths and distances at 278 sites in Macau. We provide a series of inundation maps under different tidal and sea levels. The maps that highlight adaptive strategies are essential in order to keep up with the pace of rising sea level. Read more
Carbon burial in deep-sea sediment and implications for oceanic inventories of carbon and alkalinity over the last glacial cycle Climate of the Past DOI 10.5194/cp-14-1819-2018 28 November 2018 A data-based reconstruction of carbon-bearing deep-sea sediment shows significant changes in the global burial rate over the last glacial cycle. We calculate the impact of these deep-sea changes, as well as hypothetical changes in continental shelf burial and volcanic outgassing. Our results imply that these geological fluxes had a significant impact on ocean chemistry and the global carbon isotopic ratio, and that the natural carbon cycle was not in steady state during the Holocene. Read more
