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1834 items found

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Formation of aqueous-phase α-hydroxyhydroperoxides (α-HHP): potential atmospheric impacts

The focus of this work is on quantifying the degree of the aqueous-phase formation of α-hydroxyhydroperoxides (α-HHPs) via reversible nucleophilic addition of H₂O₂ to aldehydes. Formation of this class of highly oxygenated organic hydroperoxides represents a poorly characterized aqueous-phase processing pathway that may lead to enhanced SOA formation and aerosol toxicity.

HHP): potential atmospheric impacts">Read more

Iodine-129 concentration in seawater near Fukushima before and after the accident at the Fukushima Daiichi Nuclear Power Plant

Anthropogenic radionuclides were released into the environment in large quantities by the Fukushima Daiichi Nuclear Power Plant (1FNPP) accident. To evaluate accident-derived ¹²⁹I, the ¹²⁹I concentrations in seawater before and after the accident were compared.

Impacts of aircraft emissions on the air quality near the ground

The continuing increase in demand for commercial aviation transport raises questions about the effects of resulting emissions on the environment. The purpose of this study is to investigate, using a global chemistry transport model, to what extent aviation emissions outside the boundary layer influence air quality in the boundary layer.

Palaeoclimatological perspective on river basin hydrometeorology: case of the Mekong Basin

Our main aim in this paper is to develop a river basin scale approach for assessing interannual hydrometeorological and discharge variability on long, palaeological, time scales. For the development of the basin-wide approach, we used the Mekong River basin as a case study area, although the approach is also intended to be applicable to other basins.

Classifying organic materials by oxygen-to-carbon elemental ratio to predict the activation regime of Cloud Condensation Nuclei (CCN)

The present results suggest that atmospheric particles dominated by hydrocarbon-like organic components do not activate (i.e., insoluble regime) whereas those dominated by oxygenated organic components activate (i.e., highly soluble regime) for typical atmospheric cloud life cycles.

CCN)">Read more

Instant tsunami early warning based on real-time GPS – Tohoku 2011 case study

Natural Hazards and Earth System Sciences
DOI 10.5194/nhess-13-1285-2013
17 May 2013

Taking the 2011 Tohoku earthquake as an example, we demonstrate the ability of real-time GPS to provide qualified tsunami early warning within minutes. We show that in case of the Tohoku earthquake, it would be feasible to provide accurate tsunami warning as soon as 3 min after the beginning of the earthquake.

GPS – Tohoku 2011 case study">Read more

Reducing cloud obscuration of MODIS snow cover area products by combining spatio-temporal techniques with a probability of snow approach

This study develops a rule-based, multistep method for removing clouds from MODIS snow cover area images. The methods used include combining images from more than one satellite, time interpolation, spatial interpolation, and estimation of the probability of snow occurrence based on topographic information.

MODIS snow cover area products by combining spatio-temporal techniques with a probability of snow approach">Read more

Comparative assessment of predictions in ungauged basins – Part 1: Runoff-hydrograph studies

The objective of this assessment is to compare studies predicting runoff hydrographs in ungauged catchments. The aim is to learn from the differences and similarities between catchments in different locations, and to interpret the differences in performance in terms of the underlying climate and landscape controls.

Elusive drought: uncertainty in observed trends and short- and long-term CMIP5 projections

Our results highlight the inherent difficulty of drought quantification and the considerable likelihood range of drought projections, but also indicate regions where drought is consistently found to increase. In other regions, wide likelihood range should not be equated with low drought risk, since potential scenarios include large drought increases in key agricultural and ecosystem regions.

Surface pathway of radioactive plume of TEPCO Fukushima NPP1 released ¹³⁴Cs and ¹³⁷Cs

¹³⁴Cs and ¹³⁷Cs were released to the North Pacific Ocean by two major likely pathways, direct discharge from the Fukushima NPP1 accident site and atmospheric deposition off Honshu Islands of Japan, east and northeast of the site. High density observations of ¹³⁴Cs and ¹³⁷Cs in the surface water were carried out by 17 cruises of cargo ships and several research vessel cruises from March 2011 till March 2012.

TEPCO Fukushima NPP1 released ¹³⁴Cs and ¹³⁷Cs">Read more

MERIS-based ocean colour classification with the discrete Forel–Ule scale

In this paper we present a new algorithm that has the merit of using the full spectral information in the visible domain to characterize natural waters in a simple and globally valid way. This Forel–Ule MERIS (FUME) algorithm converts the normalized multiband reflectance information into a discrete set of numbers using uniform colourimetric functions.

MERIS-based ocean colour classification with the discrete Forel–Ule scale">Read more

Possible effects on avionics induced by terrestrial gamma-ray flashes

Natural Hazards and Earth System Sciences
DOI 10.5194/nhess-13-1127-2013
30 April 2013

Terrestrial gamma-ray flashes (TGFs) are impulsive (intrinsically sub-millisecond) events associated with lightning in powerful thunderstorms. We address in this article the issue of the possible susceptibility of typical aircraft electronics exposed to TGF particle, gamma ray and neutron irradiation.

McMaster Mesonet soil moisture dataset: description and spatio-temporal variability analysis

This paper introduces and describes the hourly, high-resolution soil moisture dataset continuously recorded by the McMaster Mesonet located in the Hamilton-Halton Watershed in Southern Ontario, Canada.

Bacteriohopanepolyols record stratification, nitrogen fixation and other biogeochemical perturbations in Holocene sediments of the central Baltic Sea

We studied bacteriohopanepolyols (BHPs), lipids of specific bacterial groups, in a sediment core from the central Baltic Sea (Gotland Deep) and found considerable differences between the distinct stages of the Baltic Sea’s history.

Nitrous oxide emissions from European agriculture – an analysis of variability and drivers of emissions from field experiments

Nitrous oxide emissions from a network of agricultural experiments in Europe were used to explore the relative importance of site and management controls of emissions. At each site, a selection of management interventions were compared within replicated experimental designs in plot-based experiments.

Recent variability of the solar spectral irradiance and its impact on climate modelling

We summarize here our current knowledge of solar spectral irradiance variability and its impact on Earth’s climate.

Vertical distributions of plutonium isotopes in marine sediment cores off the Fukushima coast after the Fukushima Dai-ichi Nuclear Power Plant accident

To obtain the vertical distribution of Pu isotopes in marine sediments and to better assess the possible contamination of Pu from the Fukushima Dai-ichi Nuclear Power Plant accident in the marine environment, we determined the activities of ^239+240Pu and ²⁴¹Pu as well as the atom ratios of ²⁴⁰Pu/²³⁹Pu and ²⁴¹Pu/²³⁹Pu in sediment core samples collected in the western North Pacific off Fukushima from July 2011 to July 2012.

Flood-initiating catchment conditions: a spatio-temporal analysis of large-scale soil moisture patterns in the Elbe River basin

While the large-scale meteorological conditions have been classified and successfully linked to floods, this is lacking for the large-scale pre-event catchment conditions. Therefore, we propose classifying soil moisture as a key variable of pre-event catchment conditions and investigating the link between soil moisture patterns and flood occurrence in the Elbe River basin.

Oxidation of SO₂ by stabilized Criegee intermediate (sCI) radicals as a crucial source for atmospheric sulfuric acid concentrations

The effect of increased reaction rates of stabilized Criegee intermediates (sCIs) with SO₂ to produce sulfuric acid is investigated using data from two different locations, SMEAR II, Hyytiälä, Finland, and Hohenpeissenberg, Germany.

Inverse estimation of source parameters of oceanic radioactivity dispersion models associated with the Fukushima accident

With combined use of the ocean–atmosphere simulation models and field observation data, we evaluate the parameters associated with the total caesium-137 amounts of the direct release into the ocean and atmospheric deposition over the western North Pacific caused by the accident of Fukushima Daiichi nuclear power plant that occurred in March 2011.

Scenario and modelling uncertainty in global mean temperature change derived from emission-driven global climate models

We compare future changes in global mean temperature in response to different future scenarios which, for the first time, arise from emission-driven rather than concentration-driven perturbed parameter ensemble of a global climate model.

Short- and long-term consequences of larval stage exposure to constantly and ephemerally elevated carbon dioxide for marine bivalve populations

Experiments were performed to assess the short-term (days) and long-term (months) consequences of larval stage exposure to varying CO₂ concentrations for calcifying bivalves. The findings suggested that high CO₂ has a cascading negative physiological impact on bivalve larvae stemming in part from lower calcification rates.

Ice-shelf buttressing and the stability of marine ice sheets

Ice-shelf buttressing and the stability of marine-type ice sheets are investigated numerically. Buttressing effects are analysed for a situation where a stable grounding line is located on a bed sloping upwards in the direction of flow.

Interpreting muon radiographic data in a fault zone: possible application to geothermal reservoir detection and monitoring

Geoscientific Instrumentation, Methods and Data Systems
DOI 10.5194/gi-2-145-2013
27 March 2013

In this report, the data taken by Tanaka et al. (2011) are reanalyzed to estimate the porosity distribution as a function of a distance from the fault gouge. The result shows a similar pattern of the porosity distribution as measured by borehole sampling at Nojima fault.

The influence of climate change on flood risks in France – first estimates and uncertainty analysis

Natural Hazards and Earth System Sciences
DOI 10.5194/nhess-13-809-2013
27 March 2013

This paper proposes a methodology to project the possible evolution of river flood damages due to climate change, and applies it to mainland France.

Mechanisms causing reduced Arctic sea ice loss in a coupled climate model

The fully coupled climate model HadGEM1 produces one of the most accurate simulations of the historical record of Arctic sea ice seen in the IPCC AR4 multi-model ensemble. In this study, we examine projections of sea ice decline out to 2030, produced by two ensembles of HadGEM1 with natural and anthropogenic forcings included.

Meteorological observations on the northern Chilean coast during VOCALS-REx

Surface coastal observations from two automatic weather stations at Paposo (~25° S) and radiosonde observations at Paposo and Iquique (~20° S) were carried out during VOCALS-REx (VAMOS Ocean-Cloud-Atmosphere-Land Study Regional Experiment).

VOCALS-REx">Read more

Host model uncertainties in aerosol radiative forcing estimates: results from the AeroCom Prescribed intercomparison study

In this AeroCom Prescribed intercomparison study we systematically isolate and quantify host model uncertainties on aerosol forcing experiments through prescription of identical aerosol radiative properties in twelve participating models.

The CM SAF SSM/I-based total column water vapour climate data record: methods and evaluation against re-analyses and satellite

The European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) Satellite Application Facility on Climate Monitoring (CM SAF) aims at the provision and sound validation of well documented Climate Data Records (CDRs) in sustained and operational environments. In this study, a total column water vapour path climatology from CM SAF is presented and inter-compared to water vapour data records from various data sources.

SAF SSM/I-based total column water vapour climate data record: methods and evaluation against re-analyses and satellite">Read more

Direct linking of Greenland and Antarctic ice cores at the Toba eruption (74 ka BP)

In this work we suggest a direct synchronization of Greenland and Antarctic ice cores at the Toba eruption based on matching of a pattern of bipolar volcanic spikes. Annual layer counting between volcanic spikes in both cores allows for a unique match.

Local and global perspectives on the virtual water trade

Recent studies on fluxes of virtual water are showing how the global food and goods trade interconnects the water resources of different and distant countries, conditioning the local water balances. This paper presents and discusses the assessment of virtual water fluxes between a single country and its network of trading partners, delineating a country’s virtual water budget in space and time (years 1986–2010).

A generalized Damköhler number for classifying material processing in hydrological systems

Assessing the potential for transfer of pollutants and nutrients across catchments is of primary importance under changing land use and climate. This paper focuses on the dynamic balance between transport and material transformation, and defines material connectivity as the effective transfer of material between elements of the hydrological cycle.

Estimating the Greenland ice sheet surface mass balance contribution to future sea level rise using the regional atmospheric climate model MAR

To estimate the sea level rise originating from changes in surface mass balance of the Greenland ice sheet, we present 21st century climate projections obtained with the regional climate model MAR (Modèle Atmosphérique Régional), forced by output of three CMIP5 (Coupled Model Intercomparison Project Phase 5) general circulation models.

The Geminid meteor shower during the ECOMA sounding rocket campaign: specular and head echo radar observations

The ECOMA (Existence of Charge state Of meteoric smoke particles in the Middle Atmosphere) sounding rocket campaign was conducted during the Geminid meteor shower in December 2010 in order to explore whether there is a change of the properties of meteoric smoke particles due to the stream.

ECOMA sounding rocket campaign: specular and head echo radar observations">Read more

Quantifying the uncertainty in simulating global tropospheric composition due to the variability in global emission estimates of Biogenic Volatile Organic Compounds

In this study we examine the contribution of biogenic volatile organic compounds towards global tropospheric composition using the global 3-D chemistry transport model TM5 and the recently developed modified CB05 chemical mechanism.

Application of soil quality indices to assess the status of agricultural soils irrigated with treated wastewaters

In this work two soil quality indices were used to evaluate the effects of irrigation with treated wastewater in soils. The indices were developed studying different soil properties in undisturbed soils in SE Spain, and the relationships between soil parameters were established using multiple linear regressions.

A statistical analysis of insurance damage claims related to rainfall extremes

In this paper, a database of water-related insurance damage claims related to private properties and content was analysed. The aim was to investigate whether the probability of occurrence of rainfall-related damage was associated with the intensity of rainfall.

Surface undulations of Antarctic ice streams tightly controlled by bedrock topography

In our work we use recently acquired airborne radar data for the Rutford Ice Stream and Evans Ice Stream, and we show that the surface response of fast-flowing ice is highly sensitive to bedrock irregularities with wavelengths of several ice thicknesses.

A unified approach to infrared aerosol remote sensing and type specification

Here we use high resolution infrared measurements for aerosol type differentiation, exploiting, in that part of spectrum, the dependency of their refractive index on wavelength. We review existing detection methods and present a unified detection method based on linear discrimination analysis.

An unknown oxidative metabolism substantially contributes to soil CO₂ emissions

The respiratory release of CO₂ from soils is a major determinant of the global carbon cycle. It is traditionally considered that this respiration is an intracellular metabolism consisting of complex biochemical reactions carried out by numerous enzymes and co-factors. Here we show that the endoenzymes released from dead organisms are stabilised in soils and have access to suitable substrates and co-factors to permit function.

Ion motion in the current sheet with sheared magnetic field – Part 1: Quasi-adiabatic theory

We present a theory of trapped ion motion in the magnetotail current sheet with a constant dawn–dusk component of the magnetic field. Particle trajectories are described analytically using the quasi-adiabatic invariant corresponding to averaging of fast oscillations around the tangential component of the magnetic field.

Radiative forcing of the direct aerosol effect from AeroCom Phase II simulations

We report on the AeroCom Phase II direct aerosol effect (DAE) experiment where 16 detailed global aerosol models have been used to simulate the changes in the aerosol distribution over the industrial era. All 16 models have estimated the radiative forcing of the anthropogenic DAE, and have taken into account anthropogenic sulphate, black carbon and organic aerosols from fossil fuel, biofuel, and biomass burning emissions.

The effect of hygroscopicity on eddy covariance estimates of sea-spray aerosol fluxes: a comparison of high-rate and bulk correction methods

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.

The importance of glacier and forest change in hydrological climate-impact studies

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.

Application of the Statistical Oxidation Model (SOM) to Secondary Organic Aerosol formation from photooxidation of C₁₂ alkanes

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-NO_xconditions, based upon data from the Caltech chambers.

SOM) to Secondary Organic Aerosol formation from photooxidation of C₁₂ alkanes">Read more

Brief Communication: Expansion of meltwater lakes on the Greenland Ice Sheet

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.

High-latitude cooling associated with landscape changes from North American boreal forest fires

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.

What could have caused pre-industrial biomass burning emissions to exceed current rates?

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.

Identifying urban sources as cause of elevated grass pollen concentrations using GIS and remote sensing

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.

GIS and remote sensing">Read more

On the nature of rainfall intermittency as revealed by different metrics and sampling approaches

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.