The effect of hygroscopicity on eddy covariance estimates of sea-spray aerosol fluxes: a comparison of high-rate and bulk correction methods Atmospheric Measurement Techniques DOI 10.5194/amt-6-323-2013 13 February 2013 Here we describe a method of correcting aerosol spectra for relative humidity induced size variations at the high frequency (10 Hz) measurement timescale, where counting statistics are poor and the spectral shape cannot be well represented by a simple power law. Read more
The importance of glacier and forest change in hydrological climate-impact studies Hydrology and Earth System Sciences DOI 10.5194/hess-17-619-2013 11 February 2013 Changes in land cover alter the water balance components of a catchment, due to strong interactions between soils, vegetation and the atmosphere. Therefore, hydrological climate impact studies should also integrate scenarios of associated land cover change. To reflect two severe climate-induced changes in land cover, we applied scenarios of glacier retreat and forest cover increase that were derived from the temperature signals of the climate scenarios used in this study. Read more
Application of the Statistical Oxidation Model (SOM) to Secondary Organic Aerosol formation from photooxidation of C12 alkanes Atmospheric Chemistry and Physics DOI 10.5194/acp-13-1591-2013 8 February 2013 We apply the Statistical Oxidation Model of Cappa and Wilson (2012) to model the formation of the secondary organic aerosol from the formation of the four C12 alkanes, dodecane, 2-methyl undecane, cyclododecane and hexylcyclohexane, under both high- and low-NOxconditions, based upon data from the Caltech chambers. Read more
Brief Communication: Expansion of meltwater lakes on the Greenland Ice Sheet The Cryosphere DOI 10.5194/tc-7-201-2013 1 February 2013 Forty years of satellite imagery reveal that meltwater lakes on the margin of the Greenland Ice Sheet have expanded substantially inland to higher elevations with warming. These lakes are important because they provide a mechanism for bringing water to the ice bed, causing sliding. Read more
High-latitude cooling associated with landscape changes from North American boreal forest fires Biogeosciences DOI 10.5194/bg-10-699-2013 1 February 2013 Here we simulated changes in forest composition due to altered burn area using a stochastic model of fire occurrence, historical fire data from national inventories, and succession trajectories derived from remote sensing. Read more
What could have caused pre-industrial biomass burning emissions to exceed current rates? Climate of the Past DOI 10.5194/cp-9-289-2013 31 January 2013 Recent studies based on trace gas mixing ratios in ice cores and charcoal data surprisingly indicate that biomass burning emissions over the past millennium exceeded contemporary emissions by up to a factor of 4 for certain time periods. We have analysed how emissions from several landscape biomass burning sources could have fluctuated to yield emissions that are in correspondence with recent results based on ice core mixing ratios of carbon monoxide and its isotopic signature measured at South Pole station. Read more
Identifying urban sources as cause of elevated grass pollen concentrations using GIS and remote sensing Biogeosciences DOI 10.5194/bg-10-541-2013 29 January 2013 We examine here the hypothesis that during flowering, the grass pollen concentrations at a specific site reflect the distribution of grass pollen sources within a few kilometres of this site. We perform this analysis on data from a measurement campaign in the city of Aarhus (Denmark) using three pollen traps and by comparing these observations with a novel inventory of grass pollen sources. Read more
On the nature of rainfall intermittency as revealed by different metrics and sampling approaches Hydrology and Earth System Sciences DOI 10.5194/hess-17-355-2013 29 January 2013 Results of this work may be useful to improve the calibration of stochastic algorithms used to downscale coarse rainfall predictions of climate and weather forecasting models, as well as the parameterization of intensity-duration-frequency curves, adopted for land planning and design of civil infrastructures. Read more
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