Similarity of climate control on base flow and perennial stream density in the Budyko framework Hydrology and Earth System Sciences DOI 10.5194/hess-17-315-2013 25 January 2013 Perennial stream density (DP), which is obtained from the high resolution National Hydrography Dataset, for 185 watersheds declines monotonically with climate aridity index, and an inversely proportional function is proposed to model the relationship between DPand the ratio of potential evaporation to precipitation. Read more
Prediction, time variance, and classification of hydraulic response to recharge in two karst aquifers Hydrology and Earth System Sciences DOI 10.5194/hess-17-281-2013 24 January 2013 Many karst aquifers are rapidly filled and depleted and therefore are likely to be susceptible to changes in short-term climate variability. Here we explore methods that could be applied to model site-specific hydraulic responses, with the intent of simulating these responses to different climate scenarios from high-resolution climate models. Read more
Development of stroboscopic muography Geoscientific Instrumentation, Methods and Data Systems DOI 10.5194/gi-2-41-2013 24 January 2013 Conventional muon radiography has concentrated on non-destructive studies of stationary objects with relatively long exposure times required to achieve sufficient muon statistics. A muon detection system with real time readings and a high spatial resolution detector, enables the investigation of dynamic processes in a stroboscopic mode, where image frames are synchronized with the phases of the dynamic target. Read more
A scaling approach to project regional sea level rise and its uncertainties Earth System Dynamics DOI 10.5194/esd-4-11-2013 23 January 2013 Here, we present an alternative approach to derive regional sea level changes for a range of emission and land ice melt scenarios, combining probabilistic forecasts of a simple climate model (MAGICC6) with the new CMIP5 general circulation models. Our regional sea level projections and the diagnosed uncertainties provide an improved basis for coastal impact analysis and infrastructure planning for adaptation to climate change. Read more
Aerosol decadal trends – Part 1: In-situ optical measurements at GAW and IMPROVE stations Atmospheric Chemistry and Physics DOI 10.5194/acp-13-869-2013 22 January 2013 Since the aerosol variables are not normally distributed, three different methods (the seasonal Mann-Kendall test associated with the Sen’s slope, the generalized least squares fit associated with an autoregressive bootstrap algorithm for confidence intervals, and the least-mean square fit applied to logarithms of the data) were applied to detect the long-term trends and their magnitudes. Read more
Aerosol decadal trends – Part 2: In-situ aerosol particle number concentrations at GAW and ACTRIS stations Atmospheric Chemistry and Physics DOI 10.5194/acp-13-895-2013 22 January 2013 We have analysed the trends of total aerosol particle number concentrations (N) measured at long-term measurement stations involved either in the Global Atmosphere Watch (GAW) and/or EU infrastructure project ACTRIS. This work provides a useful comparison analysis for modelling studies of trends in aerosol number concentrations. Read more
Thermodynamics, maximum power, and the dynamics of preferential river flow structures at the continental scale Hydrology and Earth System Sciences DOI 10.5194/hess-17-225-2013 22 January 2013 Here we describe the organization and dynamics of drainage systems using thermodynamics, focusing on the generation, dissipation and transfer of free energy associated with river flow and sediment transport. Read more
Current state of glaciers in the tropical Andes: a multi-century perspective on glacier evolution and climate change The Cryosphere DOI 10.5194/tc-7-81-2013 22 January 2013 The aim of this paper is to provide the community with a comprehensive overview of the studies of glaciers in the tropical Andes conducted in recent decades leading to the current status of the glaciers in the context of climate change. In terms of changes in surface area and length, we show that the glacier retreat in the tropical Andes over the last three decades is unprecedented since the maximum extension of the Little Ice Age (LIA, mid-17th–early 18th century). Read more
Efficient determination of vehicle emission factors by fuel use category using on-road measurements: downward trends on Los Angeles freight corridor I-710 Atmospheric Chemistry and Physics DOI 10.5194/acp-13-347-2013 11 January 2013 We developed an alternative method that links real-time on-road pollutant measurements from a mobile platform with real-time traffic data, and allows efficient calculation of both the average and the spread of vehicle emission factors for light-duty gasoline-powered vehicles and heavy-duty diesel-powered vehicles. Read more
Time scale of the largest imaginable magnetic storm Nonlinear Processes in Geophysics DOI 10.5194/npg-20-19-2013 8 January 2013 The depression of the horizontal magnetic field at Earth’s equator for the largest imaginable magnetic storm has been estimated (Vasyliūnas, 2011a) as −Dst ~ 2500 nT. The obvious related question, analysed in this paper, is how long it would take the solar wind to supply the energy content of this largest storm. Read more
Tide-surge interaction in the English Channel Natural Hazards and Earth System Sciences DOI 10.5194/nhess-12-3709-2012 19 December 2012 The English Channel is characterised by strong tidal currents and a wide tidal range, such that their influence on surges is expected to be non-negligible. In order to better assess storm surges in this zone, tide-surge interactions are investigated. Read more
Management, regulation and environmental impacts of nitrogen fertilization in northwestern Europe under the Nitrates Directive; a benchmark study Biogeosciences DOI 10.5194/bg-9-5143-2012 14 December 2012 Implementation of the Nitrates Directive (NiD) and its environmental impacts were compared for member states in the northwest of the European Union (Ireland, United Kingdom, Denmark, the Netherlands, Belgium, Northern France and Germany). The main sources of data were national reports for the third reporting period for the NiD (2004–2007) and results of the MITERRA-EUROPE model. Read more
Stratospheric winds, transport barriers and the 2011 Arctic ozone hole Nonlinear Processes in Geophysics DOI 10.5194/npg-19-687-2012 12 December 2012 We consider the issue of what constitutes suitable environmental conditions for the formation and maintenance of a polar ozone hole. Our discussion focuses on the importance of the stratospheric wind field and, in particular, the importance of a high latitude zonal jet, which serves as a meridional transport barrier both prior to ozone hole formation and during the ozone hole maintenance phase. Read more
The stability of grounding lines on retrograde slopes The Cryosphere DOI 10.5194/tc-6-1497-2012 12 December 2012 The stability of marine ice sheets grounded on beds that slope upwards in the overall direction of flow is investigated numerically in two horizontal dimensions. We give examples of stable grounding lines on such retrograde slopes illustrating that marine ice sheets are not unconditionally unstable in two horizontal dimensions. Read more
Internal respiration of Amazon tree stems greatly exceeds external CO2 efflux Biogeosciences DOI 10.5194/bg-9-4979-2012 6 December 2012 Here, we studied gas exchange from stems of tropical forest trees using a new approach to better understand respiration in an ecosystem that plays a key role in the global carbon cycle. Read more
The link between great earthquakes and the subduction of oceanic fracture zones Solid Earth DOI 10.5194/se-3-447-2012 5 December 2012 We construct a model for the geometry of subduction coupling zones and combine it with global geophysical data sets to demonstrate that the occurrence of great (magnitude ≥ 8) subduction earthquakes is strongly biased towards regions associated with intersections of oceanic fracture zones and subduction zones. Read more
No statistically significant effect of a short-term decrease in the nucleation rate on atmospheric aerosols Atmospheric Chemistry and Physics DOI 10.5194/acp-12-11573-2012 4 December 2012 We use a global aerosol microphysics model to determine whether a 10 day reduction of 15% in the nucleation rate could generate a statistically significant response in aerosol concentrations and optical properties. Read more
Ocean acidification limits temperature-induced poleward expansion of coral habitats around Japan Biogeosciences DOI 10.5194/bg-9-4955-2012 4 December 2012 Using results from four coupled global carbon cycle-climate models combined with in situ observations, we estimate the effects of future global warming and ocean acidification on potential habitats for tropical/subtropical and temperate coral communities in the seas around Japan. Read more
Effects of land cover change on temperature and rainfall extremes in multi-model ensemble simulations Earth System Dynamics DOI 10.5194/esd-3-213-2012 26 November 2012 The impact of historical land use induced land cover change on regional-scale climate extremes is examined using four climate models within the Land Use and Climate, IDentification of robust impacts project. Read more
Activity and abundance of denitrifying bacteria in the subsurface biosphere of diffuse hydrothermal vents of the Juan de Fuca Ridge Biogeosciences DOI 10.5194/bg-9-4661-2012 22 November 2012 Based on our rate measurements, and on published data on hydrothermal fluid fluxes and residence times, we estimated that up to ~10 Tg N yr−1could globally be removed in the subsurface biosphere of hydrothermal vents systems, thus, representing a small fraction of the total marine N loss (~275 to > 400 Tg N yr−1). Read more