High spatial resolution imaging of methane and other trace gases with the airborne Hyperspectral Thermal Emission Spectrometer (HyTES) Atmospheric Measurement Techniques DOI 10.5194/amt-9-2393-2016 1 June 2016 Using data from a new airborne Hyperspectral Thermal Emission Spectrometer (HyTES) instrument, we present a technique for the detection and wide-area mapping of emission plumes of methane and other atmospheric trace gas species over challenging and diverse environmental conditions with high spatial resolution, that permits direct attribution to sources in complex environments. Read more
Will a perfect model agree with perfect observations? The impact of spatial sampling Atmospheric Chemistry and Physics DOI 10.5194/acp-16-6335-2016 24 May 2016 We show that evaluating global aerosol model data with observations of very different spatial scales (200 vs. 10 km) can lead to large discrepancies, solely due to different spatial sampling. Strategies for reducing these sampling errors are developed and tested using a set of high-resolution model simulations. Read more
Retrieving atmospheric turbulence information from regular commercial aircraft using Mode-S and ADS-B Atmospheric Measurement Techniques DOI 10.5194/amt-9-2253-2016 23 May 2016 This paper is presenting a feasibility study focused on methods of estimating the turbulence intensity based on a class of navigational messages routinely broadcast by the commercial aircraft (known as ADS-B and Mode-S). Using this kind of information could have potentially significant impact on aviation safety. Three methods have been investigated. Read more
Investigating the impact of land-use land-cover change on Indian summer monsoon daily rainfall and temperature during 1951–2005 using a regional climate model Hydrology and Earth System Sciences DOI 10.5194/hess-20-1765-2016 10 May 2016 Regional climate model (RegCM4) simulations demonstrate that part of the observed decrease in moderate rainfall events during the summer monsoon season over central India from 1951 to 2005 is attributed to anthropogenically induced land-use land-cover change (LULCC). LULCC also partly explains the observed warming trend in the daily mean and maximum temperatures over India. This study demonstrates the importance of LULCC in the context of regional climate change over India. Read more
Alluvial plain dynamics in the southern Amazonian foreland basin Earth System Dynamics DOI 10.5194/esd-7-453-2016 10 May 2016 This paper analyses the behaviour of 12 tributaries of the Río Mamoré and their influence on alluvial plain dynamics. These rivers are extremely active: between 1984 and 2014, 7 of these 12 rivers underwent a total of 41 crevasses and 29 avulsions. Most of the sedimentary load of these rivers is deposited on the alluvial plains before they reach the Mamoré. Crevasses and avulsions are not controlled by ENSO cycles, but rather are the result of intrabasinal processes. Read more
Bayesian statistical ionospheric tomography improved by incorporating ionosonde measurements Atmospheric Measurement Techniques DOI 10.5194/amt-9-1859-2016 28 April 2016 We validate 2-D ionospheric tomography reconstructions against EISCAT incoherent scatter radar measurements. The method is based on Bayesian statistical inversion. We employ ionosonde measurements for the choice of the prior distribution parameters and use a sparse matrix approximation for the computations. This results in a computationally efficient tomography algorithm with clear probabilistic interpretation. We find that ionosonde measurements improve the reconstruction significantly. Read more
Mapping turbulent diffusivity associated with oceanic internal lee waves offshore Costa Rica Ocean Science DOI 10.5194/os-12-601-2016 26 April 2016 Lee waves play a significant role in ocean mixing but are difficult to study with traditional casts, moorings, and tows due to their stationary nature and limited spatial extent. We develop a new method to estimate turbulent diffusivity from seismic data and find elevated levels of turbulence associated with lee waves in the mid-water and around the seafloor that are 5 times greater than surrounding waters and 50 times greater than open-ocean diffusivities. Read more
A Late Pleistocene sea level stack Climate of the Past DOI 10.5194/cp-12-1079-2016 26 April 2016 This study presents an average of seven Late Pleistocene sea level records, which improves the signal-to-noise ratio for estimates of sea level change during glacial cycles of the past 800 000 years. Read more
Revolutions in energy input and material cycling in Earth history and human history Earth System Dynamics DOI 10.5194/esd-7-353-2016 22 April 2016 We identify six past revolutions in energy input and material cycling in Earth and human history. We find that human energy use has now reached a magnitude comparable to the biosphere, and conclude that a prospective sustainability revolution will require scaling up new solar energy technologies and the development of much more efficient material recycling systems. Our work was inspired by recognising the connections between Earth system science and industrial ecology at the “LOOPS” workshop. Read more
Differential climate impacts for policy-relevant limits to global warming: the case of 1.5 ∘C and 2 ∘C Earth System Dynamics DOI 10.5194/esd-7-327-2016 21 April 2016 We present for the first time a comprehensive assessment of key climate impacts for the policy relevant warming levels of 1.5 °C and 2 °C above pre-industrial levels. We report substantial impact differences in intensity and frequency of extreme weather events, regional water availability and agricultural yields, sea-level rise and risk of coral reef loss. The increase in climate impacts is particularly pronounced in tropical and sub-tropical regions. Read more
Effects of wood chip amendments on the revegetation performance of plant species on eroded marly terrains in a Mediterranean mountainous climate (Southern Alps, France) Solid Earth DOI 10.5194/se-7-599-2016 15 April 2016 This paper presents the results of two experiments of revegetation techniques in context of water erosion and mountainous Mediterranean climate. We studied the interest of a wood chip amendment, applied on soil surface (mulch), and its interaction with plant development. The use of different plant species and the monitoring on three growing seasons (with climatic variations) allow us to specify the interest of wood chip mulch to improve revegetation especially in erosion and drought conditions. Read more
The link between marine sediment records and changes in Holocene Saharan landscape: simulating the dust cycle Climate of the Past DOI 10.5194/cp-12-1009-2016 15 April 2016 We demonstrate for the first time the direct link between dust accumulation in marine sediment cores and Saharan land surface by simulating the mid-Holocene and pre-industrial dust cycle as a function of Saharan land surface cover and atmosphere-ocean conditions using the coupled atmosphere-aerosol model ECHAM6-HAM2.1. Mid-Holocene surface characteristics, including vegetation cover and lake surface area, are derived from proxy data and simulations. Read more
Combined fluvial and pluvial urban flood hazard analysis: concept development and application to Can Tho city, Mekong Delta, Vietnam Natural Hazards and Earth System Sciences DOI 10.5194/nhess-16-941-2016 13 April 2016 Many urban areas experience both fluvial and pluvial floods, thus this study aims to analyse fluvial and pluvial flood hazards as well as combined pluvial and fluvial flood hazards. This combined fluvial-pluvial flood hazard analysis is performed in a tropical environment for Can Tho city in the Mekong Delta. The final results are probabilistic hazard maps, showing the maximum inundation caused by floods of different magnitudes along with an uncertainty estimation. Read more
Non-deforestation fire vs. fossil fuel combustion: the source of CO2 emissions affects the global carbon cycle and climate responses Biogeosciences DOI 10.5194/bg-13-2137-2016 13 April 2016 We simulated both fire pulses and stable fire regimes and found the resulting climatic impacts to be irreconcilable with equivalent amounts of CO2 emissions produced by fossil fuel combustion. Consequently, side-by-side comparisons of fire and fossil fuel CO2 emissions—implicitly implying that they have similar effects—should be avoided. Our study calls for the explicit representation of fire in climate models in order to improve our understanding of its impacts in the Earth system. Read more
Early warning signals of tipping points in periodically forced systems Earth System Dynamics DOI 10.5194/esd-7-313-2016 13 April 2016 We find early warnings of abrupt changes in complex dynamical systems such as the climate where the usual early warning indicators do not work. In particular, these are systems that are periodically forced, for example by the annual cycle of solar insolation. We show these indicators are good theoretically in a general setting then apply them to a specific system, that of the Arctic sea ice, which has been conjectured to be close to such a tipping point. We do not find evidence of it. Read more
Aura OMI observations of regional SO2 and NO2 pollution changes from 2005 to 2015 Atmospheric Chemistry and Physics DOI 10.5194/acp-16-4605-2016 13 April 2016 We examine changes in SO2 and NO2 over the world’s most polluted regions during the first decade of Aura OMI observations. Over the eastern US, both NO2 and SO2 levels decreased by 40% and 80%, respectively. OMI confirmed large reductions in SO2 over eastern Europe’s largest coal power plants. The North China Plain has the world’s most severe SO2 pollution, but a decreasing trend been observed since 2011, with a 50% reduction in 2012-2014. India’s SO2 and NO2 levels are growing at a fast pace. Read more
Statistical analysis of magnetotail fast flows and related magnetic disturbances Annales Geophysicae DOI 10.5194/angeo-34-399-2016 12 April 2016 This study presents an investigation on the occurrence of fast flows in the magnetotail using the complete available data set of the THEMIS spacecraft for the years 2007 to 2015. First, basic statistical findings concerning velocity distributions, occurrence rates, group structures and key features of 16 000 events are presented using Superposed Epoch and Minimum Variance Analysis techniques. Read more
Kinetic isotope effects of 13CH3D + OH and 13CH3D + OH from 278 to 313 K Atmospheric Chemistry and Physics DOI 10.5194/acp-16-4439-2016 11 April 2016 We present experimental kinetic isotope effects (KIE) for the OH oxidation of CH3D and 13CH3D and their temperature dependence. Our determination of the 13CH3D+OH KIE is novel and we find no “clumped” isotope effect within the experimental uncertainty. Read more
A multiproxy approach to understanding the “enhanced” flux of organic matter through the oxygen-deficient waters of the Arabian Sea Biogeosciences DOI 10.5194/bg-13-2077-2016 8 April 2016 Drifting sediment traps were deployed in the oxygen-deficient waters of the Arabian Sea, where the sinking flux is less attenuated than in more oxic waters. Six mechanisms that might explain this “enhanced flux” were evaluated using literature and data. In the upper 500m, evidence was found supporting an oxygen effect and/or changes in the efficiency of the microbial loop, including the addition of chemoautotrophic carbon to the sinking flux. Read more
Ideas and perspectives: Holocene thermokarst sediments of the Yedoma permafrost region do not increase the northern peatland carbon pool Biogeosciences DOI 10.5194/bg-13-2003-2016 6 April 2016 We investigate the properties of soils and sediments in a particular and ancient Siberian permafrost landscape. We critically examine statements from a recent study that specific permafrost landforms affected by thawed permafrost (alases) in this region contain very large quantities of peat that previous studies had failed to include because of data set biases. We conclude that there is no evidence to suggest biases in existing data sets or that alas deposits increase the northern peatland pool. Read more
Solar modulation of flood frequency in central Europe during spring and summer on interannual to multi-centennial timescales Climate of the Past DOI 10.5194/cp-12-799-2016 1 April 2016 Integrating discharge data of the River Ammer back to 1926 and a 5500-year flood layer record from an annually laminated sediment core of the downstream Ammersee allowed investigating changes in the frequency of major floods in Central Europe on interannual to multi-centennial timescales. Significant correlations between flood frequency variations in both archives and changes in the activity of the Sun suggest a solar influence on the frequency of these hydrometeorological extremes. Read more
Stratospheric ozone changes under solar geoengineering: implications for UV exposure and air quality Atmospheric Chemistry and Physics DOI 10.5194/acp-16-4191-2016 31 March 2016 Various forms of solar radiation management (SRM) have been proposed to counteract man-made climate change. However, all these countermeasures could have unintended side-effects. We add a novel perspective to this discussion by showing how atmospheric ozone changes under solar geoengineering could affect UV exposure and air pollution. This would have implications for human health and ecology. Atmospheric composition changes are therefore important to consider in the evaluation of any SRM scheme. Read more
Ice melt, sea level rise and superstorms: evidence from paleoclimate data, climate modeling, and modern observations that 2 ∘C global warming could be dangerous Atmospheric Chemistry and Physics DOI 10.5194/acp-16-3761-2016 22 March 2016 We use climate simulations, paleoclimate data and modern observations to infer that continued high fossil fuel emissions will yield cooling of Southern Ocean and North Atlantic surfaces, slowdown and shutdown of SMOC & AMOC, increasingly powerful storms and nonlinear sea level rise reaching several meters in 50-150 years, effects missed in IPCC reports because of omission of ice sheet melt and an insensitivity of most climate models, likely due to excessive ocean mixing. Read more
Coevolution of volcanic catchments in Japan Hydrology and Earth System Sciences DOI 10.5194/hess-20-1133-2016 16 March 2016 We derived indices of landscape properties as well as hydrological response and examined their relation with catchment age and climate. We found significant correlation between drainage density and baseflow index with age, but not with climate. We compared our data with data from volcanic catchments in Oregon and could confirm that baseflow index decreases with time, but also discovered that drainage density seems to stabilize after 2M years, after an initial increase due to landscape incision. Read more
Maximum wind radius estimated by the 50 kt radius: improvement of storm surge forecasting over the western North Pacific Natural Hazards and Earth System Sciences DOI 10.5194/nhess-16-705-2016 11 March 2016 We proposed an Rmax estimation method based on the radius of the 50 knot wind (R50). The data obtained during the passage of strong typhoons by a meteorological station network in the Japanese archipelago enabled us to derive the following simple formula, Rmax = 0.23 R50. The proposed method is expected to increase the reliability of storm surge prediction and contribute to disaster risk management, particularly in the western North Pacific. Read more
Imprints of climate forcings in global gridded temperature data Earth System Dynamics DOI 10.5194/esd-7-231-2016 11 March 2016 Using regression analysis, near-surface temperatures from several gridded data sets were investigated for the presence of components attributable to external climate forcings and to major internal climate variability modes, over the 1901-2010 period. The spatial patterns of local temperature response and their combination in globally averaged temperature were shown and discussed, with special focus on highlighting the inter-dataset contrasts. Read more
Phase, composition, and growth mechanism for secondary organic aerosol from the ozonolysis of α-cedrene Atmospheric Chemistry and Physics DOI 10.5194/acp-16-3245-2016 11 March 2016 A significant fraction of airborne particles, which have significant impacts on human health, visibility, and climate, are formed from the oxidation of gaseous precursors to generate low-volatility products. We show here that a sesquiterpene, α-cedrene, efficiently forms high-viscosity semisolid particles with complex composition via mechanisms that involve the highly reactive Criegee intermediate and that high molecular weight products play an important role in new particle formation. Read more
Delaying future sea-level rise by storing water in Antarctica Earth System Dynamics DOI 10.5194/esd-7-203-2016 10 March 2016 Sea level will continue to rise for centuries. We investigate the option of delaying sea-level rise by pumping ocean water onto Antarctica. Due to wave propagation ice is discharged much faster back into the ocean than expected from pure advection. A millennium-scale storage of >80% of the additional ice requires a distance of >700km from the coastline. The pumping energy required to elevate ocean water to mitigate a sea-level rise of 3mm/yr exceeds 7% of current global primary energy supply. Read more
Upwellings mitigated Plio-Pleistocene heat stress for reef corals on the Florida platform (USA) Biogeosciences DOI 10.5194/bg-13-1469-2016 10 March 2016 We present stable isotope proxy data and calcification records from fossil reef corals. The corals investigated derive from the Florida carbonate platform and are of middle Pliocene to early Pleistocene age. From the data we infer an environment subject to intermittent upwelling on annual to decadal timescales. Calcification rates were enhanced during periods of upwelling. This is likely an effect of dampened SSTs during the upwelling. Read more
Recent summer sea ice thickness surveys in Fram Strait and associated ice volume fluxes The Cryosphere DOI 10.5194/tc-10-523-2016 8 March 2016 We present an extensive data set of ground-based and airborne electromagnetic ice thickness measurements covering Fram Strait in summer between 2001 and 2012. An investigation of back trajectories of surveyed sea ice using satellite-based sea ice motion data allows us to examine the connection between thickness variability, ice age and source area. In addition, we determine across and along strait gradients in ice thickness and associated volume fluxes. Read more
The airborne mass spectrometer AIMS – Part 1: AIMS-H2O for UTLS water vapor measurements Atmospheric Measurement Techniques DOI 10.5194/amt-9-939-2016 7 March 2016 We present the development of a new airborne mass spectrometer AIMS-H2O for the fast and accurate measurement of water vapor in the upper troposphere and lower stratosphere. The high accuracy needed for e.g. quantification of atmospheric water vapor transport processes or cloud formation is achieved by an in-flight calibration of the instrument. AIMS-H2O is deployed on the DLR research aircraft HALO and Falcon where it covers a range of water vapor mixing ratios from 1 to 500 ppmv. Read more
Multi-instrument gravity-wave measurements over Tierra del Fuego and the Drake Passage – Part 1: Potential energies and vertical wavelengths from AIRS, COSMIC, HIRDLS, MLS-Aura, SAAMER, SABER and radiosondes Atmospheric Measurement Techniques DOI 10.5194/amt-9-877-2016 4 March 2016 Seven gravity-wave-resolving instruments (satellites, radiosondes and a meteor radar) are used to compare gravity-wave energy and vertical wavelength over the Southern Andes hotspot. Several conclusions are drawn, including that limb sounders and the radar show strong positive correlations. Radiosondes and AIRS weakly anticorrelate with other instruments and we see strong correlations with local stratospheric winds. Short-timescale variability is larger than the seasonal cycle. Read more
Bulk meltwater flow and liquid water content of snowpacks mapped using the electrical self-potential (SP) method The Cryosphere DOI 10.5194/tc-10-433-2016 29 February 2016 We show that strong electrical self-potential fields are generated in melting in in situ snowpacks at Rhone Glacier and Jungfraujoch Glacier, Switzerland. We conclude that the electrical self-potential method is a promising snow and firn hydrology sensor, owing to its suitability for sensing lateral and vertical liquid water flows directly and minimally invasively, complementing established observational programs and monitoring autonomously at a low cost. Read more
World’s soils are under threat SOIL DOI 10.5194/soil-2-79-2016 29 February 2016 The Intergovernmental Technical Panel on Soils has completed the first State of the World’s Soil Resources Report. The gravest threats were identified for all the regions of the world. This assessment forms a basis for future soil monitoring. The quality of soil information available for policy formulation must be improved. Read more
Proof of concept: temperature-sensing waders for environmental sciences Geoscientific Instrumentation, Methods and Data Systems DOI 10.5194/gi-5-45-2016 29 February 2016 Temperature-sensor-incorporated waders worn by the public can give scientists an additional source of information on stream water-groundwater interaction. A pair of waders was equipped with a thermistor and calibrated in the lab. Field tests in a deep polder ditch with a known localized groundwater contribution showed that the waders are capable of identifying the boil location. This can be used to decide where the most interesting places are to do more detailed and more expensive research. Read more
All-clear for gourmets: truffles not radioactive Biogeosciences DOI 10.5194/bg-13-1145-2016 25 February 2016 Although ranging among the most expensive gourmet foods, it remains unclear whether truffles accumulate radioactivity at a harmful level comparable to other fungi. Insignificant radiocaesium concentrations in specimens from Switzerland, Germany, France, Italy, and Hungary provide an all-clear for truffle hunters and cultivators in Europe as well as dealers and customers from around the world. Read more
Apparent increase in coccolithophore abundance in the subtropical North Atlantic from 1990 to 2014 Biogeosciences DOI 10.5194/bg-13-1163-2016 25 February 2016 In this study, we combine phytoplankton pigment data with particulate inorganic carbon and chlorophyll measurements from the satellite record to assess recent trends in phytoplankton dynamics in the North Atlantic subtropical gyre, with a focus on coccolithophores. We show that coccolithophores in the North Atlantic have been increasing in abundance. Correlations suggest that they are responding positively to increasing inorganic carbon from anthropogenic inputs in the upper mixed layer. Read more
Atmospheric significance of aeolian salts in the sandy deserts of northwestern China Solid Earth DOI 10.5194/se-7-191-2016 4 February 2016 Salt archives in sediments are critical to understanding a number of geochemical processes in the earth surface conditions. This study presents a physical and geochemical survey into aeolian salts in the Chinese deserts to explore their possible climatic implications. The results suggest the aeolian salts are atmospheric origin without local geological limits. It is a latent indicator in onefold depositional environment but not so in diverse conditions. Palaeoenvironmental use should be careful. Read more
Runoff- and erosion-driven transport of cattle slurry: linking molecular tracers to hydrological processes Biogeosciences DOI 10.5194/bg-13-551-2016 1 February 2016 Our interdisciplinary research brings together methodologies from hydrology, soil science and biogeochemistry to address key questions about the transport of cattle slurry in the environment. The paper provides a novel approach to trace dissolved and particulate components of cattle slurry through an experimental hillslope system. This work provides one of the first examples of using biomarkers to assess the effects of slope gradient and rainfall intensity on the movement of slurry derived-OM. Read more
Integrating a mini catchment with mulching for soil water management in a sloping jujube orchard on the semiarid Loess Plateau of China Solid Earth DOI 10.5194/se-7-167-2016 1 February 2016 We integrated fish-scale pits with mulching to test whether this integration could improve soil water conservation. The results showed that integrating fish-scale pits with mulching could conserve significantly more soil water by increasing infiltration and decreasing evaporation, and showed greater soil water storage and degree of soil water compensation compared to fish-scale pits alone. In addition, jujube branches exerted better mulching effects than maize straw. Read more
Does the Budyko curve reflect a maximum-power state of hydrological systems? A backward analysis Hydrology and Earth System Sciences DOI 10.5194/hess-20-479-2016 28 January 2016 We derived mathematical formulations of relations between relative wetness and gradients driving run-off and evaporation for a one-box model such that, when conductances are optimized with the maximum power principle, the model leads exactly to a point on the Budyko curve. With dry spells and dynamics in actual evaporation added, the model compared well with catchment observations without calibrating any parameter. The maximum-power principle may thus be used to derive the Budyko curve. Read more
Efficacy of bedrock erosion by subglacial water flow Earth Surface Dynamics DOI 10.5194/esurf-4-125-2016 27 January 2016 In regions formerly, or currently, covered by glaciers, landscapes have largely been shaped by glaciers. Glaciers erode bedrock through three main mechanisms: abrasion, quarrying, and subglacial meltwater erosion (SME). The latter, however, remains enigmatic. We present the first numerical modelling study of bedrock erosion by subglacial water and find that SME is negligible compared to abrasion and quarrying across the glacier, but its localization can explain the formation of bedrock channels. Read more
Trail impact monitoring in Rocky Mountain National Park, USA Solid Earth DOI 10.5194/se-7-115-2016 26 January 2016 Rocky Mountain National Park is one of the most visited national parks in the United States. 95% of the park is managed as wilderness. This paper examines the impacts of trampling on the vegetation and soil along selected trails. Trail widening and soil loss are the most visible types of trail degradation. Insights into the influence of different factors (use level, topography) can lead to the selection of appropriate management measures to avoid or minimize negative consequences. Read more
CO2 emission and structural characteristics of two calcareous soils amended with municipal solid waste and plant residue Solid Earth DOI 10.5194/se-7-105-2016 26 January 2016 Following the application of organic amendment treatments, the increased organic carbon and total porosity values, as compared to the control treatment, were greater in the loamy sand soil than in the clay loam soil. Moreover, compared to the microbial respiration of control plots, the application of municipal solid waste resulted in higher levels of microbial respiration from the clay loam soil than from the loamy sand soil, whereas the reverse was found for alfalfa residue. Read more
Modeling global water use for the 21st century: the Water Futures and Solutions (WFaS) initiative and its approaches Geoscientific Model Development DOI 10.5194/gmd-9-175-2016 21 January 2016 The Water Futures and Solutions (WFaS) initiative coordinates its work with other ongoing scenario efforts for the sake of establishing a consistent set of new global water scenarios based on the shared socio-economic pathways (SSPs) and the representative concentration pathways (RCPs). The WFaS “fast-track” assessment uses three global water models, H08, PCR-GLOBWB, and WaterGAP, to provide the first multi-model analysis of global water use for the 21st century based on the water scenarios. Read more
Mapping of steady-state electric fields and convective drifts in geomagnetic fields – Part 2: The IGRF Annales Geophysicae DOI 10.5194/angeo-34-67-2016 19 January 2016 The method of electric field mapping along geomagnetic field lines, derived in an accompanying paper, is applied to the International Geomagnetic Reference Field. Formulae for the geomagnetic field gradient tensor are derived and these are used in a software package developed to map the electric field. A number of examples are presented illustrating the method. The method will be of importance in conjugate studies of ionospheric convection when the external magnetic field can be neglected. Read more
Mapping of steady-state electric fields and convective drifts in geomagnetic fields – Part 1: Elementary models Annales Geophysicae DOI 10.5194/angeo-34-55-2016 19 January 2016 This paper introduces a new method for mapping electric fields in the magnetosphere along geomagnetic field lines. This is important for conjugate studies of electric fields measured in the ionosphere by SuperDARN radars, and at spacecraft carrying electric field probes. First elementary methods in a dipole field are reviewed and then the theory of of a new method described for general magnetic field models. The method is tested in a dipole model with a Harris magnetotail field. Read more
Overview of the Chemistry-Aerosol Mediterranean Experiment/Aerosol Direct Radiative Forcing on the Mediterranean Climate (ChArMEx/ADRIMED) summer 2013 campaign Atmospheric Chemistry and Physics DOI 10.5194/acp-16-455-2016 19 January 2016 The aim of this article is to present an experimental campaign over the Mediterranean focused on aerosol-radiation measurements and modeling. Results indicate an important atmospheric loading associated with a moderate absorbing ability of mineral dust. Observations suggest a complex vertical structure and size distributions characterized by large aerosols within dust plumes. The radiative effect is highly variable, with negative forcing over the Mediterranean and positive over northern Africa. Read more
Aggregation in environmental systems – Part 1: Seasonal tracer cycles quantify young water fractions, but not mean transit times, in spatially heterogeneous catchments Hydrology and Earth System Sciences DOI 10.5194/hess-20-279-2016 19 January 2016 Catchment mean transit times have been widely inferred from seasonal cycles of environmental tracers in precipitation and streamflow. Here I show that these cycles yield strongly biased estimates of mean transit times in spatially heterogeneous catchments (and, by implication, in real-world catchments). However, I also show that these cycles can be used to reliably estimate the fraction of “young” water in streamflow, meaning water that fell as precipitation less than roughly 2–3 months ago. Read more
Aggregation in environmental systems – Part 2: Catchment mean transit times and young water fractions under hydrologic nonstationarity Hydrology and Earth System Sciences DOI 10.5194/hess-20-299-2016 19 January 2016 Here I show that seasonal tracer cycles yield strongly biased estimates of mean transit times in nonstationary catchments (and, by implication, in real-world catchments). However, they can be used to reliably estimate the fraction of “young” water in streamflow, meaning water that fell as precipitation less than roughly 2–3 months ago. This young water fraction varies systematically between high and low flows and may help in characterizing controls on stream chemistry. Read more