bluuebunny/crossref_metadata_2025 huggingface dataset:
Air quality resolution for health impact assessment: influence of regional characteristics
Authors: Thompson T. M. , Saari R. K. , Selin N. E.
Published: January 2014

Abstract. We evaluate how regional characteristics of population and background pollution might impact the selection of optimal air quality model resolution when calculating the human health impacts of changes to air quality. Using an approach consistent with air quality policy evaluation, we use a regional chemical transport model (CAMx) and a health benefit mapping program (BenMAP) to calculate the human health impacts associated with changes in ozone and fine particulate matter resulting from an emission reduction scenario. We evaluate this same scenario at 36, 12 and 4 km resolution for nine regions in the eastern US representing varied characteristics. We find that the human health benefits associated with changes in ozone concentrations are sensitive to resolution. This finding is especially strong in urban areas where we estimate that benefits calculated using coarse resolution results are on average two times greater than benefits calculated using finer scale results. In three urban areas we analyzed, results calculated using 36 km resolution modeling fell outside the uncertainty range of results calculated using finer scale modeling. In rural areas the influence of resolution is less pronounced with only an 8% increase in the estimated health impacts when using 36 km resolution over finer scales. In contrast, health benefits associated with changes in PM2.5 concentrations were not sensitive to resolution and did not follow a pattern based on any regional characteristics evaluated. The largest difference between the health impacts estimated using 36 km modeling results and either 12 or 4 km results was at most ±10% in any region. Several regions showed increases in estimated benefits as resolution increased (opposite the impact seen with ozone modeling), while some regions showed decreases in estimated benefits as resolution increased. In both cases, the dominant contribution was from secondary PM. Additionally, we found that the health impacts calculated using several individual concentration–response functions varied by a larger amount than the impacts calculated using results modeled at different resolutions. Given that changes in PM2.5 dominate the human health impacts, and given the uncertainty associated with human health response to changes in air pollution, we conclude that, when estimating the human health benefits associated with decreases in ozone and PM2.5 together, the benefits calculated at 36 km resolution agree, within errors, with the benefits calculated using fine (12 km or finer) resolution modeling when using the current methodology for assessing policy decisions.
Does the POA–SOA split matter for global CCN formation?
Authors: Trivitayanurak W. , Adams P. J.
Published: January 2014

Abstract. A model of carbonaceous aerosols has been implemented in the TwO-Moment Aerosol Sectional (TOMAS) microphysics module in the GEOS-Chem chemical transport model (CTM), a model driven by assimilated meteorology. Inclusion of carbonaceous emissions alongside pre-existing treatments of sulfate and sea-salt aerosols increases the number of emitted primary aerosol particles by a factor of 2.5 and raises annual-average global cloud condensation nuclei at 0.2% supersaturation (CCN(0.2%)) concentrations by a factor of two. Compared to the prior model without carbonaceous aerosols, this development improves the model prediction of condensation nuclei with dry diameter larger than 10 nm (CN10) number concentrations significantly from −45% to −7% bias when compared to long-term observations. Inclusion of carbonaceous particles also largely eliminates a tendency for the model to underpredict higher cloud condensation nuclei (CCN) concentrations. Similar to other carbonaceous models, the model underpredicts organic carbon (OC) and elemental carbon (EC) mass concentrations by a factor of 2 when compared to EMEP and IMPROVE observations. Because primary organic aerosol (POA) and secondary organic aerosol (SOA) affect aerosol number size distributions via different microphysical processes, we assess the sensitivity of CCN production, for a fixed source of organic aerosol (OA) mass, to the assumed POA–SOA split in the model. For a fixed OA budget, we found that CCN(0.2%) decreases nearly everywhere as the model changes from a world dominated by POA emissions to one dominated by SOA condensation. POA is about twice as effective per unit mass at CCN production compared to SOA. Changing from a 100% POA scenario to a 100% SOA scenario, CCN(0.2%) concentrations in the lowest model layer decrease by about 20%. In any scenario, carbonaceous aerosols contribute significantly to global CCN. The SOA–POA split has a significant effect on global CCN, and the microphysical implications of POA emissions versus SOA condensation appear to be at least as important as differences in chemical composition as expressed by the hygroscopicity of OA. These findings stress the need to better understand carbonaceous aerosols loadings, the global SOA budget, microphysical pathways of OA formation (emissions versus condensation) as well as chemical composition to improve climate modeling.
Aerosol microphysics simulations of the Mt. Pinatubo eruption with the UKCA composition-climate model
Authors: Dhomse S. S. , Emmerson K. M. , Mann G. W. , Bellouin N. , Carslaw K. S. , Chipperfield M. P. , Hommel R. , Abraham N. L. , Telford P. , Braesicke P. , Dalvi M. , Johnson C. E. , O'Connor F. , Morgenstern O. , Pyle J. A. , Deshler T. , Zawodny J. M. , Thomason L. W.
Published: January 2014

Abstract. We have enhanced the capability of a microphysical aerosol-chemistry module to simulate the atmospheric aerosol and precursor gases for both tropospheric and stratospheric conditions. Using the Mount Pinatubo eruption (June 1991) as a test case, we evaluate simulated aerosol properties in a composition-climate model against a range of satellite and in-situ observations. Simulations are performed assuming an injection of 20 Tg SO2 at 19–27 km in tropical latitudes, without any radiative feedback from the simulated aerosol. In both quiescent and volcanically perturbed conditions, simulated aerosol properties in the lower stratosphere show reasonable agreement with the observations. The model captures the observed timing of the maximum aerosol optical depth (AOD) and its decay timescale in both tropics and Northern Hemisphere (NH) mid-latitudes. There is also good qualitative agreement with the observations in terms of spatial and temporal variation of the aerosol effective radius (Reff), which peaks 6–8 months after the eruption. However, the model shows significant biases against some observational data sets. Simulated AOD and Surface Area Density (SAD) in the tropics are substantially higher than the gap-filled satellite data products during the first 6 months after the eruption. The model shows consistently weaker enhancement in Reff compared to satellite and in-situ measurements. Simulated aerosol particle size distribution is also compared to NH mid-latitude in-situ balloon sounding measurements of size-resolved number concentrations. Before the eruption, the model captures the observed profiles of lower stratospheric particle number concentrations with radii larger than 5, 150 and 250 nm (N5, N150 and N250) very well. However, in the first 6 months after the eruption, the model shows high bias in N5 concentrations in the lower stratosphere, suggesting too strong nucleation. Following particle growth via condensation and coagulation, this bias in the finest particles propagates into a factor 2 high bias in N150. Our comparison suggests that new particle formation in the initial phase of large eruptions, and subsequent particle growth to optically-active sizes, might be playing an important role in determining the magnitude of the climate impacts from volcanoes like Pinatubo.
Long-term MAX-DOAS network observations of NO2 in Russia and Asia (MADRAS) during 2007–2012: instrumentation, elucidation of climatology, and comparisons with OMI satellite observations and global model simulations
Authors: Kanaya Y. , Irie H. , Takashima H. , Iwabuchi H. , Akimoto H. , Sudo K. , Gu M. , Chong J. , Kim Y. J. , Lee H. , Li A. , Si F. , Xu J. , Xie P.-H. , Liu W.-Q. , Dzhola A. , Postylyakov O. , Ivanov V. , Grechko E. , Terpugova S. , Panchenko M.
Published: January 2014

Abstract. We conducted long-term network observations using standardized Multi-Axis Differential optical absorption spectroscopy (MAX-DOAS) instruments in Russia and ASia (MADRAS) from 2007 onwards. At seven locations (Cape Hedo, Fukue, and Yokosuka in Japan, Hefei in China, Gwangju in Korea, and Tomsk and Zvenigorod in Russia) with different levels of pollution, we obtained 80 927 retrievals of tropospheric NO2 vertical column density (TropoNO2VCD) and aerosol optical depth (AOD). In the technique, the optimal estimation of the TropoNO2VCD and its profile was performed using aerosol information derived from O4 absorbances simultaneously observed at 460–490 nm. This large data set was used to analyze NO2 climatology systematically, including temporal variations from the seasonal to the diurnal scale. The results were compared with Ozone Monitoring Instrument (OMI) satellite observations and global model simulations. Two NO2 retrievals of OMI satellite data (NASA ver. 2.1 and Dutch OMI NO2 (DOMINO) ver. 2.0) generally showed close correlations with those derived from MAX-DOAS observations, but had low biases of ~50%. The bias was distinct when NO2 was abundantly present near the surface and when the AOD was high, suggesting that the aerosol shielding effect could be important, especially for clean sites where the difference could not be attributed to the spatial inhomogeneity. Except for constant biases, the satellite observations showed nearly perfect seasonal agreement with MAX-DOAS observations, suggesting that the analysis of seasonal features of the satellite data were robust. The prevailing seasonal patterns with a wintertime maximum implied the dominance of anthropogenic emissions around our sites. The presence of weekend reductions at Yokosuka and Gwangju suggested the dominance of emissions from diesel vehicles, with significant weekly cycles, whereas the absence of such a reduction at Hefei suggested the importance of other sources. A global chemical transport model, MIROC-ESM-CHEM, was validated for the first time with respect to background NO2 column densities during summer at Cape Hedo and Fukue in the clean marine atmosphere.
Constraining mass–diameter relations from hydrometeor images and cloud radar reflectivities in tropical continental and oceanic convective anvils
Authors: Fontaine E. , Schwarzenboeck A. , Delanoë J. , Wobrock W. , Leroy D. , Dupuy R. , Protat A.
Published: January 2014

Abstract. In this study the density of hydrometeors in tropical clouds is derived from a combined analysis of particle images from 2-D-array probes and associated reflectivities measured with a Doppler cloud radar on the same research aircraft. The mass–diameter m(D) relationship is expressed as a power law with two unknown coefficients (pre-factor, exponent) that need to be constrained from complementary information on hydrometeors, where absolute ice density measurement methods do not apply. Here, at first an extended theoretical study of numerous hydrometeor shapes simulated in 3-D and arbitrarily projected on a 2-D plane allowed to constrain the temporal evolution of the exponent of the mass–diameter relationship with that of the exponent of the surface–diameter relationship that is measured by the 2-D-array probes. The pre-factor is then constrained from theoretical simulations of the radar reflectivities matching the measured reflectivities along the aircraft trajectory. The study has been performed as part of the Megha-Tropiques satellite project, where two types of mesoscale convective systems (MCS) have been investigated: (i) above the African Continent and (ii) above the Indian Ocean. In general, both mass-diameter coefficients (pre-factor and exponent) decrease with decreasing temperature, the decrease is more pronounced for oceanic MCS. The condensed water contents (CWC) calculated from particle size distributions (PSD) and m(D) also decrease with altitude while the concentrations of the hydrometeors increase with altitude. The calculated values of CWC are largest for continental MCS.
Trajectory matching of ozonesondes and MOZAIC measurements in the UTLS – Part 2: Application to the global ozonesonde network
Authors: Staufer J. , Staehelin J. , Stübi R. , Peter T. , Tummon F. , Thouret V.
Published: January 2014

Abstract. Both balloon-borne electrochemical ozonesondes and MOZAIC (measurements of ozone, water vapour, carbon monoxide and nitrogen oxides by in-service Airbus aircraft) provide very valuable data sets for ozone studies in the upper troposphere/lower stratosphere (UTLS). Although MOZAIC's highly accurate UV-photometers are regularly inspected and recalibrated annually, recent analyses cast some doubt on the long-term stability of their ozone analysers. To investigate this further, we perform a 16 yr comparison (1994–2009) of UTLS ozone measurements from balloon-borne ozonesondes and MOZAIC. The analysis uses fully three-dimensional trajectories computed from ERA-Interim (European Centre for Medium-Range Weather Forecasts Re-analysis) wind fields to find matches between the two measurement platforms. Although different sensor types (Brewer-Mast and Electrochemical Concentration Cell ozonesondes) were used, most of the 28 launch sites considered show considerable differences of up to 25% compared to MOZAIC in the mid-1990s, followed by a systematic tendency to smaller differences of around 5–10% in subsequent years. The reason for the difference before 1998 remains unclear, but observations from both sondes and MOZAIC require further examination to be reliable enough for use in robust long-term trend analyses starting before 1998. According to our analysis, ozonesonde measurements at tropopause altitudes appear to be rather insensitive to changing the type of the Electrochemical Concentration Cell ozonesonde, provided the cathode sensing solution strength remains unchanged. Scoresbysund (Greenland) showed systematically 5% higher readings after changing from Science Pump Corporation sondes to ENSCI Corporation sondes, while a 1.0% KI cathode electrolyte was retained.
Tropical tropospheric ozone column retrieval for GOME-2
Authors: Valks P. , Hao N. , Gimeno Garcia S. , Loyola D. , Dameris M. , Jöckel P. , Delcloo A.
Published: January 2014

Abstract. This paper presents the operational retrieval of tropical tropospheric ozone columns (TOC) from the Second Global Ozone Monitoring Experiment (GOME-2) instruments using the convective-cloud-differential (CCD) method. The retrieval is based on total ozone and cloud property data provided by the GOME Data Processor (GDP) 4.7, and uses above-cloud and clear-sky ozone column measurements to derive a monthly mean TOC between 20° N and 20° S. Validation of the GOME-2 TOC with several tropical ozonesonde sites shows good agreement, with a high correlation between the GOME-2 and sonde measurements, and small biases within ~ 3 DU. The TOC data have been used in combination with tropospheric NO2 measurements from GOME-2 to analyse the effect of the 2009–2010 El Niño–Southern Oscillation (ENSO) on the tropospheric ozone distribution in the tropics. El-Niño induced dry conditions in September–October 2009 resulted in relatively high tropospheric ozone columns over the southern Indian Ocean and northern Australia, while La Niña conditions in September–October 2010 resulted in a strong increase in tropospheric NO2 in South America, and enhanced ozone in the eastern Pacific and South America. Comparisons of the GOME-2 tropospheric ozone data with simulations of the ECHAM/MESSy Atmospheric Chemistry (EMAC) model for 2009 El Nino conditions, illustrate the usefulness of the GOME-2 TOC measurements in evaluating chemistry climate models. Evaluation of CCMs with appropriate satellite observations helps to identify strengths and weaknesses of the model systems, providing a better understanding of driving mechanisms and adequate relations and feedbacks in the Earth atmosphere, and finally leading to improved models.
A permanent raman lidar station in the Amazon: description, characterization and first results
Authors: Barbosa H. M. J. , Barja B. , Pauliquevis T. , Gouveia D. A. , Artaxo P. , Cirino G. G. , Santos R. M. N. , Oliveira A. B.
Published: January 2014

Abstract. A permanent UV Raman Lidar station, designed to perform continuous measurements of aerosols and water vapor and aiming to study and monitor the atmosphere on the weather to climatic time scales, became operational in central Amazon in July 2011. The automated data acquisition and internet monitoring enabled extended hours of daily measurements when compared to a manually operated instrument. This paper gives a technical description of the system, presents its experimental characterization and the algorithms used for obtaining the aerosol optical properties and identifying the cloud layers. Data from one week of measurements during the dry season of 2011 were analyzed as a mean to assess the overall system capability and performance. A comparison of the aerosol optical depth from the Lidar and a co-located AERONET sun photometer showed a root mean square error of about 0.06, small compared to the range of observed AOD values (0.1 to 0.75) and to the typical AERONET AOD uncertainty (0.02). By combining nighttime measurements of the aerosol lidar ratio (50–65 sr), backtrajectories calculations and fire spots observed from satellites we showed that observed particles originated from biomass burning. Cirrus clouds were observed in 60% of our measurements. Most of the time they were distributed into three layers between 11.5 and 13.4 km a.g.l. The systematic and long-term measurements being made by this new scientific facility have the potential to significantly improve our understanding of the climatic implications of the anthropogenic changes in aerosol concentrations over the pristine Amazônia.
Photosynthetic activity buffers ocean acidification in seagrass meadows
Authors: Hendriks I. E. , Olsen Y. S. , Ramajo L. , Basso L. , Steckbauer A. , Moore T. S. , Howard J. , Duarte C. M.
Published: January 2014

Abstract. Macrophytes growing in shallow coastal zones characterised by intense metabolic activity have the capacity to modify pH within their canopy and beyond. We observed diel pH changes in shallow (5–12 m) seagrass (Posidonia oceanica) meadows spanning 0.06 pH units in September to 0.24 units in June. The carbonate system (pH, DIC, and aragonite saturation state (ΩAr)) and O2 within the meadows displayed strong diel variability driven by primary productivity, and changes in chemistry were related to structural parameters of the meadow, in particular, the leaf surface area available for photosynthesis (LAI). LAI was positively correlated to mean, max and range pHNBS and max and range ΩAr. In June, vertical mixing (as Turbulent Kinetic Energy) influenced max and min ΩAr, while in September there was no effect of hydrodynamics on the carbonate system within the canopy. Max and range ΩAr within the meadow showed a positive trend with the calcium carbonate load of the leaves, pointing to a possible link between structural parameters, ΩAr and carbonate deposition. Calcifying organisms, e.g. epiphytes with carbonate skeletons, may benefit from the modification of the carbonate system by the meadow. There is, however, concern for the ability of seagrasses to provide modifications of similar importance in the future. The predicted decline of seagrass meadows may alter the scope for alteration of pH within a seagrass meadow and in the water column above the meadow, particularly if shoot density and biomass decline, on which LAI is based. Organisms associated with seagrass communities may therefore suffer from the loss of pH buffering capacity in degraded meadows.
Calcium carbonate corrosivity in an Alaskan inland sea
Authors: Evans W. , Mathis J. T. , Cross J. N.
Published: January 2014

Abstract. Ocean acidification is the hydrogen ion increase caused by the oceanic uptake of anthropogenic CO2, and is a focal point in marine biogeochemistry, in part, because this chemical reaction reduces calcium carbonate (CaCO3) saturation states (Ω) to levels that are corrosive (i.e., Ω ≤ 1) to shell-forming marine organisms. However, other processes can drive CaCO3 corrosivity; specifically, the addition of tidewater glacial melt. Carbonate system data collected in May and September from 2009 through 2012 in Prince William Sound (PWS), a semienclosed inland sea located on the south-central coast of Alaska and ringed with fjords containing tidewater glaciers, reveal the unique impact of glacial melt on CaCO3 corrosivity. Initial limited sampling was expanded in September 2011 to span large portions of the western and central sound, and included two fjords proximal to tidewater glaciers: Icy Bay and Columbia Bay. The observed conditions in these fjords affected CaCO3 corrosivity in the upper water column (< 50 m) in PWS in two ways: (1) as spring-time formation sites of mode water with near-corrosive Ω levels seen below the mixed layer over a portion of the sound, and (2) as point sources for surface plumes of glacial melt with corrosive Ω levels (Ω for aragonite and calcite down to 0.60 and 1.02, respectively) and carbon dioxide partial pressures (pCO2) well below atmospheric levels. CaCO3 corrosivity in glacial melt plumes is poorly reflected by pCO2 or pHT, indicating that either one of these carbonate parameters alone would fail to track Ω in PWS. The unique Ω and pCO2 conditions in the glacial melt plumes enhances atmospheric CO2 uptake, which, if not offset by mixing or primary productivity, would rapidly exacerbate CaCO3 corrosivity in a positive feedback. The cumulative effects of glacial melt and air–sea gas exchange are likely responsible for the seasonal reduction of Ω in PWS, making PWS highly sensitive to increasing atmospheric CO2 and amplified CaCO3 corrosivity.
The net exchange of methane with high Arctic landscapes during the summer growing season
Authors: Emmerton C. A. , St. Louis V. L. , Lehnherr I. , Humphreys E. R. , Rydz E. , Kosolofski H. R.
Published: January 2014

Abstract. High Arctic landscapes are essentially vast cold deserts interspersed with streams, ponds and wetlands. These landscapes may be important consumers and sources of the greenhouse gas methane (CH4), though few measurements exist from this region. To quantify the flux of CH4 (FCH4) between the atmosphere and desert and wetland landscapes on northern Ellesmere Island, Canada, we made static chamber measurements at both locations over five growing seasons and eddy covariance (EC) measurements at the wetland in 2012. Chamber measurements revealed that desert soils consumed CH4 (−1.37 ± 0.10 mg-CH4 m−2 d−1) whereas the wetland emitted CH4 (+0.22 ± 0.19 mg-CH4 m−2 d−1). Desert CH4 consumption rates were positively correlated with soil temperature among years, and were similar to temperate locations, likely because of suitable landscape conditions for soil gas diffusion. Wetland FCH4 varied closely with stream discharge entering the wetland and hence extent of soil saturation. Landscape-scale FCH4 measured by EC was +1.27± 0.18 mg-CH4 m−2 d−1 and varied with soil temperature and carbon dioxide flux. FCH4 measured using EC was higher than using chambers because EC incorporated a arger, more saturated footprint of the wetland. Using EC FCH4 and quantifying the mass of CH4 entering and exiting the wetland in stream water, we determined that methanogenisis within wetland soils was the dominant source of FCH4. Low FCH4 at the wetland was likely due to a shallow organic soil layer, and thus limited carbon resources for methanogens. Considering the prevalence of dry soils in the high Arctic, our results suggest that these landscapes cannot be overlooked as important consumers of atmospheric CH4.
Comment on "Carbon farming in hot, dry coastal areas: an option for climate change mitigation" by Becker et al. (2013)
Authors: Heimann M.
Published: January 2014

Abstract. Becker et al. (2013) argue that an afforestation of 0.73 × 109 ha with Jatropha curcas plants would generate an additional terrestrial carbon sink of 4.3 PgC yr−1, enough to stabilise the atmospheric mixing ratio of carbon dioxide (CO2) at current levels. However, this is not consistent with the dynamics of the global carbon cycle. Using a well-established global carbon cycle model, the effect of adding such a hypothetical sink leads to a reduction of atmospheric CO2 levels in the year 2030 by 25 ppm compared to a reference scenario. However, the stabilisation of the atmospheric CO2 concentration requires a much larger additional sink or corresponding reduction of anthropogenic emissions.
A linear inversion method to infer exhumation rates in space and time from thermochronometric data
Authors: Fox M. , Herman F. , Willett S. D. , May D. A.
Published: January 2014

Abstract. We present a formal inverse procedure to extract exhumation rates from spatially distributed low temperature thermochronometric data. Our method is based on a Gaussian linear inversion approach in which we define a linear problem relating exhumation rate to thermochronometric age with rates being parameterized as variable in both space and time. The basis of our linear forward model is the fact that the depth to the "closure isotherm" can be described as the integral of exhumation rate, ..., from the cooling age to the present day. For each age, a one-dimensional thermal model is used to calculate a characteristic closure temperature, and is combined with a spectral method to estimate the conductive effects of topography on the underlying isotherms. This approximation to the four-dimensional thermal problem allows us to calculate closure depths for data sets that span large spatial regions. By discretizing the integral expressions into time intervals we express the problem as a single linear system of equations. In addition, we assume that exhumation rates vary smoothly in space, and so can be described through a spatial correlation function. Therefore, exhumation rate history is discretized over a set of time intervals, but is spatially correlated over each time interval. We use an a priori estimate of the model parameters in order to invert this linear system and obtain the maximum likelihood solution for the exhumation rate history. An estimate of the resolving power of the data is also obtained by computing the a posteriori variance of the parameters and by analyzing the resolution matrix. The method is applicable when data from multiple thermochronometers and elevations/depths are available. However, it is not applicable when there has been burial and reheating. We illustrate our inversion procedure using examples from the literature.
Influence of microphysical schemes on atmospheric water in the Weather Research and Forecasting model
Authors: Cossu F. , Hocke K.
Published: January 2014

Abstract. This study examines how different microphysical parameterization schemes influence orographically induced precipitation and the distributions of hydrometeors and water vapour for midlatitude summer conditions in the Weather Research and Forecasting (WRF) model. A high-resolution two-dimensional idealized simulation is used to assess the differences between the schemes in which a moist air flow is interacting with a bell-shaped 2 km high mountain. Periodic lateral boundary conditions are chosen to recirculate atmospheric water in the domain. It is found that the 13 selected microphysical schemes conserve the water in the model domain. The gain or loss of water is less than 0.81% over a simulation time interval of 61 days. The differences of the microphysical schemes in terms of the distributions of water vapour, hydrometeors and accumulated precipitation are presented and discussed. The Kessler scheme, the only scheme without ice-phase processes, shows final values of cloud liquid water 14 times greater than the other schemes. The differences among the other schemes are not as extreme, but still they differ up to 79% in water vapour, up to 10 times in hydrometeors and up to 64% in accumulated precipitation at the end of the simulation. The microphysical schemes also differ in the surface evaporation rate. The WRF single-moment 3-class scheme has the highest surface evaporation rate compensated by the highest precipitation rate. The different distributions of hydrometeors and water vapour of the microphysical schemes induce differences up to 49 W m−2 in the downwelling shortwave radiation and up to 33 W m−2 in the downwelling longwave radiation.
Frontiers in air quality modelling
Authors: Colette A. , Bessagnet B. , Meleux F. , Terrenoire E. , Rouïl L.
Published: January 2014

Abstract. The first pan-European kilometre-scale atmospheric chemistry simulation is introduced. The continental-scale air pollution episode of January 2009 is modelled with the CHIMERE offline chemistry transport model with a massive grid of 2 million horizontal points, performed on 2000 CPU of a high-performance computing system hosted by the Research and Technology Computing Center at the French Alternative Energies and Atomic Energy Commission (CCRT/CEA). Besides the technical challenge, we find that model biases are significantly reduced, especially over urban areas. The high-resolution grid also allows revisiting of the contribution of individual city plumes to the European burden of pollution, providing new insights to target the appropriate geographical level of action when designing air pollution mitigation strategies.
HEMCO v1.0: A versatile, ESMF-compliant component for calculating emissions in atmospheric models
Authors: Keller C. A. , Long M. S. , Yantosca R. M. , Da Silva A. M. , Pawson S. , Jacob D. J.
Published: January 2014

Abstract. We describe the Harvard-NASA Emission Component version 1.0 (HEMCO), a stand-alone software component for computing emissions in global atmospheric models. HEMCO determines emissions from different sources, regions and species on a user-specified grid and can combine, overlay, and update a set of data inventories and scale factors, selected by the user from a data library through the HEMCO configuration file. New emission inventories at any spatial and temporal resolution are readily added to HEMCO and can be accessed by the user without any pre-processing of the data files or modification of the source code. Emissions that depend on dynamic source types and local environmental variables such as wind speed or surface temperature are calculated in separate HEMCO extensions. HEMCO is fully compliant with the Earth System Modeling Framework (ESMF) environment. It is highly portable and can be deployed in a new model environment with only few adjustments at the top-level interface. So far, we have implemented HEMCO in the NASA GEOS-5 Earth System Model (ESM) and in the GEOS-Chem chemical transport model (CTM). By providing a widely applicable framework for specifying constituent emissions, HEMCO is designed to ease sensitivity studies and model comparisons, as well as inverse modeling in which emissions are adjusted iteratively. The HEMCO code, extensions, and data libraries are available at http://wiki.geos-chem.org/HEMCO.
Semi-Lagrangian transport of oxygen isotopes in polythermal ice sheets: implementation and first results
Authors: Goelles T. , Grosfeld K. , Lohmann G.
Published: January 2014

Abstract. Modelling the evolution of the Earth system on long timescales requires the knowledge and understanding of driving mechanisms, such as the hydrological cycle. This is dominant in all components of the Earth's system, such as atmosphere, ocean, land surfaces/vegetation and the cryosphere. Observations and measurements of stable water isotopes in climate archives can help to decipher and reconstruct climate change and its regional variations. For the cryosphere, the δ18O cycle in the current generation of Earth-System-Models is missing and an efficient and accurate tracer transport scheme is required. We describe ISOPOLIS 1.0 a modular semi-Lagrangian transport scheme of second order accuracy which is coupled to the polythermal and thermomechanical ice sheet model SICOPOLIS (version 2.9). Model skill is demonstrated by experiments with a simplified ice sheet geometry and by comparisons of simulated ice cores with data from Greenland (GRIP) and Antarctica (Vostok). The presented method is a valuable tool to investigate the transport of any kind of passive tracer inside polythermal ice sheets and is an important step to model the whole δ18O cycle.
A parameter model of gas exchange for the seasonal sea ice zone
Authors: Loose B. , McGillis W. R. , Perovich D. , Zappa C. J. , Schlosser P.
Published: January 2014

Abstract. Carbon budgets for the polar oceans require better constraint on air–sea gas exchange in the sea ice zone (SIZ). Here, we utilize advances in the theory of turbulence, mixing and air–sea flux in the ice–ocean boundary layer (IOBL) to formulate a simple model for gas exchange when the surface ocean is partially covered by sea ice. The gas transfer velocity (k) is related to shear-driven and convection-driven turbulence in the aqueous mass boundary layer, and to the mean-squared wave slope at the air–sea interface. We use the model to estimate k along the drift track of ice-tethered profilers (ITPs) in the Arctic. Individual estimates of daily-averaged k from ITP drifts ranged between 1.1 and 22 m d−1, and the fraction of open water (f) ranged from 0 to 0.83. Converted to area-weighted effective transfer velocities (keff), the minimum value of keff was 10−55 m d−1 near f = 0 with values exceeding keff = 5 m d−1 at f = 0.4. The model indicates that effects from shear and convection in the sea ice zone contribute an additional 40% to the magnitude of keff, beyond what would be predicted from an estimate of keff based solely upon a wind speed parameterization. Although the ultimate scaling relationship for gas exchange in the sea ice zone will require validation in laboratory and field studies, the basic parameter model described here demonstrates that it is feasible to formulate estimates of k based upon properties of the IOBL using data sources that presently exist.
Exploring the shallow structure of the San Ramón thrust fault in Santiago, Chile (∼33.5° S), using active seismic and electric methods
Authors: Díaz D. , Maksymowicz A. , Vargas G. , Vera E. , Contreras-Reyes E. , Rebolledo S.
Published: January 2014

Abstract. The crustal-scale west-vergent San Ramón thrust fault system at the foot of the main Andean Cordillera in central Chile is a geologically active structure with Quaternary manifestations of complex surface rupture along fault segments in the eastern border of Santiago city. From the comparison of geophysical and geological observations, we assessed the subsurface structure pattern affecting sedimentary cover and rock-substratum topography across fault scarps, which is critic for evaluating structural modeling and associated seismic hazard along this kind of faults. We performed seismic profiles with an average length of 250 m, using an array of twenty-four geophones (GEODE), and 25 shots per profile, supporting high-resolution seismic tomography for interpreting impedance changes associated to deformed sedimentary cover. The recorded traveltime refractions and reflections were jointly inverted by using a 2-D tomographic approach, which resulted in variations across the scarp axis in both velocities and reflections interpreted as the sedimentary cover-rock substratum topography. Seismic anisotropy observed from tomographic profiles is consistent with sediment deformation triggered by west-vergent thrust tectonics along the fault. Electrical soundings crossing two fault scarps supported subsurface resistivity tomographic profiles, which revealed systematic differences between lower resistivity values in the hanging wall with respect to the footwall of the geological structure, clearly limited by well-defined east-dipping resistivity boundaries. The latter can be interpreted in terms of structurally driven fluid content-change between the hanging wall and the footwall of a permeability boundary associated with the San Ramón fault. The overall results are consistent with a west-vergent thrust structure dipping ∼55° E at subsurface levels in piedmont sediments, with local complexities being probably associated to fault surface rupture propagation, fault-splay and fault segment transfer zones.
Thinking of Their Sisters:
Authors: Gregory Rabia
Published: January 2014

Fifteenth-century nuns Alijt Bake and Magdalena Beutler were both condemned for false mystical teachings but were also influential teachers whose books were widely recopied into the seventeenth century. Though both women's careers are typically considered as evidence for an antifeminist ecclesiastical crackdown on female visionaries, the popularity of their written books suggests that there were competing hermeneutics for interpreting women's visions. Through comparisons with other convent authors this essay argues that women religious and lay readers authorized women teachers for the utility of their books while men engaged in the discernment of spirits sometimes overlooked female comportment to promote the objectives of their own religious orders.
Obtaining Maximal Stability with a Septal Extension Technique in East Asian Rhinoplasty
Authors: Jeong Jae Yong
Published: January 2014

Recently, in Korea, the septal extension graft from the septum or rib has become a common method of correcting a small or short nose. The success rate of this method has led to the blind faith that it provides superior tip projection and definition, and to the failure to notice its weaknesses. Even if there is a sufficient amount of cartilage, improper separation or fixation might waste the cartilage, resulting in an inefficient operation. Appropriate resection and effective fixation are essential factors for economical rhinoplasty. The septal extension graft is a remarkable procedure since it can control the nasal tip bidirectionally and three dimensionally. Nevertheless, it has a serious drawback since resection is responsible for septal weakness. Safe resection and firm reconstruction of the framework should be carried out. Operating on the basis of the principle of "safe harvest" and rebuilding the structures is important. Further, it is important to learn several techniques to manage septal weakness, insufficient cartilage quantity, and failure of the rigid frame during the surgery.
An Introduction to the Septal Extension Graft
Authors: Kim Myung-Hoon , Choi Jeong-Hwan , Kim Min-Su , Kim Seok-Kwun , Lee Keun-Cheol
Published: January 2014

The septal extension graft is a very useful method of controlling nasal lengthening and tip projection, rotation, and shape by fixing a graft to the septum, which leads to a strong supporting structure. Enhancing graft stability is important for better long-term outcomes and minimizing complications or relapse, and even more efficient application of these methods is needed for East Asians who lack enough cartilage to be harvested in addition to possessing a weak cartilage framework. In this paper, the methods for overcoming the drawbacks of the septal extension graft, such as instability, a fixed tip, and insufficiency of cartilage, are presented, and the applications of each method for greater satisfaction with surgical outcomes are also discussed.
Elevated Aurora Kinase A Protein Expression in Diabetic Skin Tissue
Authors: Cho Moon Kyun , An Je Min , Kim Chul Han , Kang Sang Gue
Published: January 2014

BackgroundAurora kinase A (Aurora-A) plays an important role in the regulation of mitosis and cytokinesis. Dysregulated Aurora-A leads to mitotic faults and results in pathological conditions. No studies on Aurora-A expression in human diabetic skin tissue have been reported. In light of this, we explored the expression of Aurora-A in human diabetic skin tissue.

Methods Aurora-A protein was evaluated by western blotting in 6 human diabetic skin tissue and 6 normal skin specimens.

Results Increased expression of Aurora-A protein was detected in all diabetic skin tissue samples in both western blot analysis and immunohistochemical staining. However, in the case of the normal skin tissue, no bands of Aurora-A protein were detected in either the western blotting analysis or the immunohistochemical staining.

Conclusions Thus far, there have been no studies on the expression of Aurora-A in diabetic skin tissue. However, we believe that oxidative DNA damage related to the expression of Aurora-A protein and Aurora-A could be involved inhuman diabetic skin tissue.
Asymptomatic cryptococcal antigenemia is associated with mortality among HIV‐positive patients in Indonesia
Authors: Ganiem Ahmad Rizal , Indrati Agnes Rengga , Wisaksana Rudi , Meijerink Hinta , van der Ven Andre , Alisjahbana Bachti , van Crevel Reinout
Published: January 2014

Introduction

Previous studies, mostly from Africa, have shown that serum cryptococcal antigenemia may precede the development of cryptococcal meningitis and early death among patients with advanced HIV infection. We examined cryptococcal antigenemia as a risk factor for HIV‐associated mortality in Indonesia, which is experiencing a rapidly growing HIV epidemic.

Methods

We included ART‐naïve HIV patients with a CD4 cell count below 100 cells/μL and no signs of meningitis in an outpatient HIV clinic in Bandung, West Java, Indonesia. Baseline clinical data and follow‐up were retrieved from a prospective database, and cryptococcal antigen was measured in stored serum samples using a semiquantitative lateral flow assay. Cox regression analysis was used to identify factors related to mortality.

Results

Among 810 patients (median CD4 cell count 22), 58 (7.1%) had a positive cryptococcal antigen test with a median titre of 1:80 (range: 1:1 to 1:2560). Cryptococcal antigenemia at baseline was strongly associated with the development of cryptococcal meningitis and early death and loss to follow‐up. After one year, both death (22.4% vs. 11.6%; p=0.016; adjusted HR 2.19; 95% CI 1.78–4.06) and the combined endpoint of death or loss to follow‐up (67.2% vs. 40.4%; p<0.001; adjusted HR 1.57; 95% CI 1.12–2.20) were significantly higher among patients with a positive cryptococcal antigen test.

Conclusions

Cryptococcal antigenemia is common and clinically relevant among patients with advanced HIV in this setting. Routine screening for cryptococcal antigen followed by lumbar puncture and pre‐emptive antifungal treatment for those who are positive may help in reducing early mortality.
Activation-triggered subunit exchange between CaMKII holoenzymes facilitates the spread of kinase activity
Authors: Stratton Margaret , Lee Il-Hyung , Bhattacharyya Moitrayee , Christensen Sune M , Chao Luke H , Schulman Howard , Groves Jay T , Kuriyan John
Published: January 2014

The activation of the dodecameric Ca2+/calmodulin dependent kinase II (CaMKII) holoenzyme is critical for memory formation. We now report that CaMKII has a remarkable property, which is that activation of the holoenzyme triggers the exchange of subunits between holoenzymes, including unactivated ones, enabling the calcium-independent phosphorylation of new subunits. We show, using a single-molecule TIRF microscopy technique, that the exchange process is triggered by the activation of CaMKII, and that exchange is modulated by phosphorylation of two residues in the calmodulin-binding segment, Thr 305 and Thr 306. Based on these results, and on the analysis of molecular dynamics simulations, we suggest that the phosphorylated regulatory segment of CaMKII interacts with the central hub of the holoenzyme and weakens its integrity, thereby promoting exchange. Our results have implications for an earlier idea that subunit exchange in CaMKII may have relevance for information storage resulting from brief coincident stimuli during neuronal signaling.
Electronic Structures and Optical Properties of (G
a
P)n
(A
l
P)n
Short-Period Superlattices with n=1 to 6
Authors: Shibata Gakuei , Nakayama Takashi , Kamimura Hiroshi
Published: January 2014

In this study we have investigated the origin of the strong intensity of photoluminescence in the short-period
superlattices consisting of a pair of indirect-gap semiconductors GaP and AlP. For this purpose we first calculated
the electronic structures and optical properties of (GaP)
n
(AlP)
n
short-period superlattices with the clean (001) interface by the norm-conserving pseudopotential method within the local density approximation. In this calculation we showed that the clean-interface (GaP)
n
(AlP)
n
with n=3 and 2 are indirect-gap semiconductors while those with n=3 to 6 are pseudo-direct-gap semiconductors. Although the calculated layer-thickness dependence of band-gap energies is consistent with experimental results, the calculated transition strengths are one to two orders
of magnitude smaller than the observed ones. In order to solve this discrepancy, we considered four models of
disordering at the interface and investigated the effects of disordering on photoluminescence phenomena. Among
the four models, it was shown that the alloying- and ordered-interface models are favorable for transition energies,
while the antisite-interface model is favorable for transition strength.
Practical Analysis of Single Electron Pump with Harmonic Drive
Authors: Akio Iwasa Akio Iwasa , Akio Fukushima Akio Fukushima , Arkadi A. Odintsov Arkadi A. Odintsov
Published: January 2014

We study a two-gate single electron pump device with harmonic AC gate voltages. We have performed numerical and analytical calculations of quantum correction to a DC current due to the cotunneling phenomena. This correction determines the accuracy of the device in a wide range of parameters (temperature, frequency and amplitude of the gate voltage modulation). We found the crossover from adiabatic transport at lower frequencies f ≪f
cr to non-adiabatic transport at higher frequencies f ≫f
cr. The crossover frequency f
cr = { k
B
T / (e
2/ C) }2 / (A
R
T
C) is argued to be the optimal frequency of the pump operation.
Mirror Design and Alignment for X-Ray Lithography Beamlines
Authors: Kuroda Kenichi , Takashi Kaneko Takashi Kaneko
Published: January 2014

In order to improve the performance of X-ray lithography beamlines with a two toroidal mirror system, we have developed a simple yet efficient mirror design tool and a convenient alignment technique. A ray-tracing design tool named X-BEAM (X-ray beamline evaluation and arrange module) calculates a small number of rays and automatically optimizes mirror specifications in a short time. Optimization of mirror specifications proceeds by minimizing an evaluation function of power intensity uniformity and runout errors. A procedure to align mirrors using X-BEAM is also proposed. A plate which has three pinholes is inserted into the X-ray flux just in front of the first mirror. The mirror posture is uniquely determined by measuring pinhole image configuration on screens located downstream of mirrors and by deriving manipulating parameters from X-BEAM calculation. Using these design and alignment techniques, we have achieved a highly efficient beamline using a two toroidal mirror system for X-ray lithography.