Laboratory evidence of organic peroxide and peroxyhemiacetal formation in the aqueous phase and implications for aqueous OH Atmospheric Chemistry and Physics DOI 10.5194/acp-15-12867-2015 19 November 2015 This paper demonstrates organic peroxide and peroxyhemiacetal formation during aqueous photooxidation of methylglyoxal using ultra-high-resolution Fourier transform ion cyclotron resonance electrospray ionization mass spectrometry (FTICR-MS). Then, we provide simulation results of organic peroxide/peroxyhemiacetal formation in clouds and wet aerosols and discuss organic peroxides as a source of condensed-phase OH radicals and as a contributor to aqueous secondary organic aerosol (SOA). Read more
Ice water content vertical profiles of high-level clouds: classification and impact on radiative fluxes Atmospheric Chemistry and Physics DOI 10.5194/acp-15-12327-2015 9 November 2015 We discuss the shape of ice water content (IWC) vertical profiles in high ice clouds and its effect on radiative properties of these clouds, both in short- and in long-wave bands (SW and LW). We suggest a set of primitive shapes (rectangular, isosceles trapezoid, lower and upper triangle) and propose a statistical parameterization using ice water path (IWP) as a single parameter. We estimate and explain simulated differences in LW/SW atmospheric radiances for suggested IWC shapes. Read more
Reducing uncertainties in projections of Antarctic ice mass loss The Cryosphere DOI 10.5194/tc-9-2043-2015 9 November 2015 Projections of Antarctic dynamics and contribution to sea-level rise are evaluated in the light of intercomparison exercises dedicated to evaluate models’ ability of representing coastal changes. Uncertainties in projections can be substantially decreased if a selection of models is made and models that are unqualified for the representation of coastal dynamics are excluded. Read more
Modelling Mediterranean agro-ecosystems by including agricultural trees in the LPJmL model Geoscientific Model Development DOI 10.5194/gmd-8-3545-2015 5 November 2015 This study presents the inclusion of 10 Mediterranean agricultural plants in an agro-ecosystem model (LPJmL): nut trees, date palms, citrus trees, orchards, olive trees, grapes, cotton, potatoes, vegetables and fodder grasses. The model was successfully tested in three model outputs: agricultural yields, irrigation requirements and soil carbon density. With this development presented, LPJmL is now able to simulate in good detail and mechanistically the functioning of Mediterranean agriculture. Read more
Expanding the validity of the ensemble Kalman filter without the intrinsic need for inflation Nonlinear Processes in Geophysics DOI 10.5194/npg-22-645-2015 3 November 2015 The popular data assimilation technique known as the ensemble Kalman filter (EnKF) suffers from sampling errors due to the limited size of the ensemble. This deficiency is usually cured by inflating the sampled error covariances and by using localization. This paper further develops and discusses the finite-size EnKF, or EnKF-N, a variant of the EnKF that does not require inflation. It expands the use of the EnKF-N to a wider range of dynamical regimes. Read more
Local- and regional-scale measurements of CH4, δ13CH4, and C2H6 in the Uintah Basin using a mobile stable isotope analyzer Atmospheric Measurement Techniques DOI 10.5194/amt-8-4539-2015 30 October 2015 We describe an innovative instrument based on cavity ring-down spectroscopy that analyzes the stable isotopes of methane in the ambient atmosphere. This instrument was used to study atmospheric emissions from oil and gas extraction activities in the Uintah Basin in Utah. These measurements suggest that 85 ± 7% of the total emissions in the basin are from natural gas production. The easy field deployment of this instrument can enable similar regional attribution studies across the world. Read more
Regional analysis of groundwater droughts using hydrograph classification Hydrology and Earth System Sciences DOI 10.5194/hess-19-4327-2015 28 October 2015 To improve the design of drought monitoring networks and water resource management during episodes of drought, there is a need for a better understanding of spatial variations in the response of aquifers to major meteorological droughts. This paper is the first to describe a suite of methods to quantify such variations. Using an analysis of groundwater level data for a case study from the UK, the influence of catchment characteristics on the varied response of groundwater to droughts is explored. Read more
The importance of Asia as a source of black carbon to the European Arctic during springtime 2013 Atmospheric Chemistry and Physics DOI 10.5194/acp-15-11537-2015 20 October 2015 We show that during the springtime of 2013, the anthropogenic pollution particularly from sources in Asia, contributed significantly to black carbon across the European Arctic free troposphere. In contrast to previous studies, the contribution from open wildfires was minimal. Given that Asian pollution is likely to continue to rise over the coming years, it is likely that the radiative forcing in the Arctic will also continue to increase. Read more
Earthquakes and depleted gas reservoirs: which comes first? Natural Hazards and Earth System Sciences DOI 10.5194/nhess-15-2201-2015 7 October 2015 While the debate is on the possibility that the 2012 Emilia quakes could have been triggered by human activity, we studied the inverse relationship between hydrocarbon and seismicity. Overlapping a data set of gas and oil wells with a database of seismic sources, we found that only 1/19 wells falling on the largest faults is currently productive, while the highest ratio of productive wells is found outside the seismogenic sources. In general, productive gas wells are anti-correlated with faults. Read more
ECCO version 4: an integrated framework for non-linear inverse modeling and global ocean state estimation Geoscientific Model Development DOI 10.5194/gmd-8-3071-2015 6 October 2015 The ECCO v4 non-linear inverse modeling framework and its reference solution are made publicly available. The inverse estimate of ocean physics and atmospheric forcing yields a dynamically consistent and global state estimate without unidentified sources of heat and salt that closely fits in situ and satellite data. Any user can reproduce it accurately. Parametric and external model uncertainties are of comparable magnitudes and generally exceed structural model uncertainties. Read more
