Oxidation of sulfides and rapid weathering in recent landslides Earth Surface Dynamics DOI 10.5194/esurf-4-727-2016 22 September 2016 Rapid dissolution of bedrock and regolith mobilised by landslides can be an important control on rates of overall chemical weathering in mountain ranges. In this study we analysed a number of landslides and rivers in Taiwan to better understand why this occurs. We find that sulfuric acid resulting from rapid oxidation of highly reactive sulfides in landslide deposits drives the intense weathering and can set catchment-scale solute budgets. This could be a CO2source in fast-eroding mountains. Read more
Muographic data analysis method for medium-sized rock overburden inspections Geoscientific Instrumentation, Methods and Data Systems DOI 10.5194/gi-5-427-2016 21 September 2016 A paper focusing on the application of elementary particle physics to the measurements of rock overburden density structures that might be directly applicable to natural resources and undiscovered cave explorations, and even to searching for hidden chambers in historic architectural structures. Read more
A geological model for the management of subsurface data in the urban environment of Barcelona and surrounding area Solid Earth DOI 10.5194/se-7-1317-2016 16 September 2016 This study shows the need for a symbiotic relationship between government and research groups for efficient management of geologic data in urban environments. Through its implementation, both the city administration and private companies benefit from the feedback of geologic knowledge acquired during this process, thereby substantially reducing the cost of construction projects and facilitating the development of aquifer management plans. Read more
Dispersion in deep polar firn driven by synoptic-scale surface pressure variability The Cryosphere DOI 10.5194/tc-10-2099-2016 15 September 2016 The upper 50–100 m of the world’s ice sheets consists of the firn layer, a porous layer of snow that is slowly compacted by overlying snow. Understanding air movement inside the firn is critical for ice core climate reconstructions. Buizert and Severinghaus identify and describe a new mechanism of firn air movement. High- and low-pressure systems force air movement in the firn that drives strong mixing, called dispersion. Dispersion is the main mechanism for air mixing in the deep firn. Read more
Sea-ice indicators of polar bear habitat The Cryosphere DOI 10.5194/tc-10-2027-2016 14 September 2016 Polar bears, found in 19 distinct regions of the Arctic, depend on sea ice as a platform for hunting. Using satellite data of sea ice for the period 1979–2014, we found that the date of sea-ice retreat in spring is arriving weeks earlier, and the date of sea-ice advance in fall is arriving weeks later, in all 19 regions. We calculated several other measures of sea ice, which all show declines. These measures were designed to be useful for management agencies to assess polar bear habitat. Read more
Using present-day observations to detect when anthropogenic change forces surface ocean carbonate chemistry outside preindustrial bounds Biogeosciences DOI 10.5194/bg-13-5065-2016 13 September 2016 Ocean carbonate observations from surface buoys reveal that marine life is currently exposed to conditions outside preindustrial bounds at 12 study locations around the world. Seasonal conditions in the California Current Ecosystem and Gulf of Maine also exceed thresholds that may impact shellfish larvae. High-resolution observations place long-term change in the context of large natural variability: a necessary step to understand ocean acidification impacts under real-world conditions. Read more
Long-term visibility variation in Athens (1931–2013): a proxy for local and regional atmospheric aerosol loads Atmospheric Chemistry and Physics DOI 10.5194/acp-16-11219-2016 12 September 2016 Historical time series are unique sources of information for past climate and atmospheric composition change. The 82-year time series of visibility data collected at the National Observatory of Athens (NOA) was an excellent proxy for the long-term evolution of particulate pollution in the eastern Mediterranean, at times when direct aerosol measurements were missing. Evolution of particulate pollution of both local and regional origin is nicely reflected on visibility records of NOA. Read more
Interactions between climate change and human activities during the early to mid-Holocene in the eastern Mediterranean basins Climate of the Past DOI 10.5194/cp-12-1847-2016 12 September 2016 This paper focuses on early Holocene rapid climate changes in the Mediterranean zone, which are under-represented in continental archives, and on their impact on prehistoric societies from the eastern to central Mediterranean (central Anatolia, Cyprus, NE and NW Greece). Our study demonstrates the reality of hydrogeomorphological responses to early Holocene RCCs in valleys and alluvial fans and lake–marsh systems. We finally question their socio-economic and geographical adaptation capacities. Read more
Modified ion-Weibel instability as a possible source of wave activity at Comet 67P/Churyumov-Gerasimenko Annales Geophysicae DOI 10.5194/angeo-34-691-2016 31 August 2016 A new type of wave has been detected by the magnetometer of the Rosetta spacecraft close to comet P67/Churyumov-Gerasimenko. We provide the analytical model of this wave excitation from linear perturbation theory. A modified ion-Weibel instability is identified as source of this wave excited by a cometary current. The waves predominantly grow perpendicular to this current. A fan-like phase structure results from superposing the strongest growing waves in a cometary rest frame. Read more
New data on geology of the Southern Urals: a concise summary of research after the period of EUROPROBE activity Solid Earth DOI 10.5194/se-7-1269-2016 31 August 2016 The period between 1991 and 2005 was a time when many western geologists came to the Urals to get a closer look at this famous and extraordinarily rich region. The main reason was an openness policy of the USSR government, when foreigners were admitted to this area that was formerly almost closed. The co-operation of the western geologists with local specialists was very fruitful. The author aimed to describe the most interesting findings in Uralian geology after the learned guests left. Read more
Coherence among the Northern Hemisphere land, cryosphere, and ocean responses to natural variability and anthropogenic forcing during the satellite era Earth System Dynamics DOI 10.5194/esd-7-717-2016 30 August 2016 Using 3 decades of observational satellite and field data, we find that long-term changes in sea ice and sea level, plant phenology, and surface temperature are coherent with increases in atmospheric CO2 concentration and other global greenhouse gases. During the same period, natural causes of climate change should only have a net cooling long-term effect, suggesting the observed coherent pattern of changes across Earth’s biological and physical systems could only be due to human activities. Read more
Gravel threshold of motion: a state function of sediment transport disequilibrium? Earth Surface Dynamics DOI 10.5194/esurf-4-685-2016 29 August 2016 Accurately predicting gravel transport rates in mountain rivers is difficult because of feedbacks with channel morphology. River bed surfaces evolve during floods, influencing transport rates. I propose that the threshold of gravel motion is a state variable for channel reach evolution. I develop a new model to predict how transport thresholds evolve as a function of transport rate, and then use laboratory flume experiments to calibrate and validate the model. Read more
Why CO2 cools the middle atmosphere – a consolidating model perspective Earth System Dynamics DOI 10.5194/esd-7-697-2016 29 August 2016 Carbon dioxide, while warming the Earth’s surface, cools the atmosphere beyond about 15 km (the middle atmosphere). This cooling is considered a fingerprint of anthropogenic global warming, yet the physical reason behind it remains prone to misconceptions. Here we use a simple radiation model to illustrate the physical essence of stratospheric cooling, and a complex climate model to quantify how strongly different mechanisms contribute. Read more
A thermodynamic formulation of root water uptake Hydrology and Earth System Sciences DOI 10.5194/hess-20-3441-2016 29 August 2016 This theoretical paper describes the energy fluxes and dissipation along the flow paths involved in root water uptake, an approach that is rarely taken. We show that this provides useful additional insights for understanding the biotic and abiotic impediments to root water uptake. This approach shall be applied to explore efficient water uptake strategies and help locate the limiting processes in the complex soil–plant–atmosphere system. Read more
Impacts of aviation fuel sulfur content on climate and human health Atmospheric Chemistry and Physics DOI 10.5194/acp-16-10521-2016 24 August 2016 Using a coupled tropospheric chemistry-aerosol microphysics model this research paper investigates the effect of variations in aviation fuel sulfur content (FSC) on surface PM2.5 concentrations, increases in aviation-induced premature mortalities, low-level cloud condensation nuclei and radiative effect. When investigating the climatic impact of variations in FSC the ozone direct radiative effect, aerosol direct radiative effect and aerosol cloud albedo effect are quantified. Read more
Hemispherically asymmetric volcanic forcing of tropical hydroclimate during the last millennium Earth System Dynamics DOI 10.5194/esd-7-681-2016 23 August 2016 A band of intense rainfall exists near the equator known as the intertropical convergence zone, which can migrate in response to climate forcings. Here, we assess such migration in response to volcanic eruptions of varying spatial structure (Northern Hemisphere, Southern Hemisphere, or an eruption fairly symmetric about the equator). We do this using model simulations of the last millennium and link results to energetic constraints and the imprint eruptions may leave behind in past records. Read more
Satellite observations of stratospheric hydrogen fluoride and comparisons with SLIMCAT calculations Atmospheric Chemistry and Physics DOI 10.5194/acp-16-10501-2016 22 August 2016 HF, the dominant stratospheric fluorine reservoir, results from the atmospheric degradation of anthropogenic species such as CFCs, HCFCs, and HFCs. All are strong greenhouse gases, and CFCs and HCFCs deplete stratospheric ozone. We report the comparison of HF global distributions and trends measured by the ACE-FTS and HALOE satellite instruments with the output of SLIMCAT, a chemical transport model. The global HF trends reveal a slowing down in the rate of increase of HF since the 1990s. Read more
Annual Greenland accumulation rates (2009–2012) from airborne snow radar The Cryosphere DOI 10.5194/tc-10-1739-2016 11 August 2016 Contemporary climate warming over the Arctic is accelerating mass loss from the Greenland Ice Sheet through increasing surface melt, emphasizing the need to closely monitor surface mass balance in order to improve sea-level rise predictions. Here, we quantify the net annual accumulation over the Greenland Ice Sheet, which comprises the largest component of surface mass balance, at a higher spatial resolution than currently available using high-resolution, airborne-radar data. Read more
A review of marine geomorphometry, the quantitative study of the seafloor Hydrology and Earth System Sciences DOI 10.5194/hess-20-3207-2016 9 August 2016 Geomorphometry, the science of quantitative terrain characterization, has traditionally focused on the investigation of terrestrial landscapes. More recently, a suite of geomorphometric techniques have been applied to characterize the seafloor. The dynamic, four-dimensional nature of the marine environment and differences in data collection methods cause issues for geomorphometry that are specific to marine applications. This article offers the first review of marine geomorphometry to date. Read more
Large gain in air quality compared to an alternative anthropogenic emissions scenario Atmospheric Chemistry and Physics DOI 10.5194/acp-16-9771-2016 4 August 2016 Three 30-year simulations of past atmospheric composition changes were performed using different anthropogenic emissions of pollutants accounting or not for the applied air quality legislation and accounting for the year–to–year observed climate and natural emissions variability. The actual benefit of applied legislation along with technological advances is higher than what is usually calculated by a simple comparison of today’s atmosphere against a constant anthropogenic emissions simulation. Read more