bluuebunny/crossref_metadata_2025 huggingface dataset:
1830 ex imo
Authors: Diaz Brigitte
Published: April 2010

Cette communication se propose d’identifier la « génération de 1830 » à travers ses rapports avec l’intime et l’intimisme. Le goût de l’intime qui caractérise cette génération se manifeste dans les pratiques nouvelles d’écriture de soi que sont lettres et journaux intimes. Il est relayé et amplifié par la voix d’écrivains qui vont faire de ce tropisme intimiste un trait générationnel. Si le repli dans le champ de l’intériorité est producteur de nouvelles valeurs existentielles et esthétiques, il est aussi vécu par les contemporains de Musset comme une malédiction de l’Histoire. Dans cette cristallisation de l’image d’une génération « condamnée à l’intime », George Sand et Sainte-Beuve sont des opérateurs essentiels. À travers les analyses et les représentations qu’ils tendent à leurs contemporains dans leurs préfaces, leurs articles mais aussi dans leurs fictions, qui relèvent de ce qu’on appelle alors « l’école intime », ils ont contribué à forger une conscience générationnelle.
The Meaning of Home
Authors: Molony Sheila L.
Published: April 2010

Practice-based initiatives have emphasized the need to provide “homelike” environments in long-term care. This study adds to the discourse on the meaning of home by synthesizing several individual qualitative studies using Noblit and Hare’s method of meta-ethnography. The purpose of this larger synthesis is to bring the findings from several discrete studies into a larger interpretive perspective that will lead to ongoing theory and practice development to enable experiences of home during residential transition, thereby informing nursing praxis in creating and shaping therapeutic environments.
La ocupación laboral de los convivientes con afectados por discapacidades. Un análisis multivariable
Authors: Spijker Jeroen , Pérez Díaz Julio
Published: April 2010

La relación entre el rol de cuidador y la actividad laboral ha cambiado mucho durante las últimas décadas, influida por la evolución del contexto demográfico, sanitario y sociológico, pero también por una política sociosanitaria que persigue la máxima implicación de los familiares. utilizando la Encuesta sobre Discapacidades, Deficiencias y Estado de Salud, y mediante el análisis de regresión logística multivariable, investigamos cómo se relacionan en los hogares la convivencia o cuidado de personas con discapacidad y la ocupación laboral de los convivientes. Los resultados confirman que el determinante principal es la asunción del rol de cuidador y no el sexo, pero también se comprueba que los roles complementarios, masculinos y femeninos, se hacen más intensos en los hogares que deben afrontar la discapacidad de alguno de sus miembros, en detrimento de la igualación entre hombres y mujeres.
Deep-Diving Manned Research Submersibles
Authors: Rona Peter A.
Published: April 2010

The global fleet of deep-diving manned research submersibles comprises thirteen human occupied vehicles (HOV), eleven of which are presently operational, managed by different agencies in France, Japan, Russia and the United States. The basic components of these submersibles are similar,
but significant differences exist in capabilities and operational styles. The most efficient and effective use of deep-diving HOV’s is as the final tool after the dive target has been located by a systematic search procedure of closing range using ships and unmanned vehicles (towed,
ROV, or AUV) as platforms for various measurement, imaging and sampling methods. A key role continues to exist for deep-diving HOV’s as the ultimate tool to investigate the deep ocean when judiciously used by the trained observer in coordination with other shipboard and unmanned deep
submergence methods. The scientific value of the human presence within the deep ocean is irreplaceable by other methods.
Marine Aquaculture in the United States: A Review of Current and Future Policy and Management Challenges
Authors: DeVoe M. Richard
Published: April 2010

Aquaculture in the United States has the potential to become a major growth industry in the 21st Century. However, a number of issues continue to constrain the development of marine aquaculture in the United States. The campier and diverse nature of the industry, conflicts with other,
more traditional uses of the nation’s coastal and ocean waters, environmental concerns, and the existing legal and regulatory climate all contribute to this situation. If the domestic marine aquaculture industry is to succeed and grow in the future, these issues must be resolved. First,
the United States must reevaluate and reaffirm the nation’s aquaculture policy. Second, the couuntry must support sustainable marine aquaculture. Marine aquaculture in coastal and offshore waters of the United States must be developed with an eye toward sustainability—with a goal
of producing products while conserving natural resources. Third, assuming the United States is truly committed to the development of the marine aquaculture industry, mechanisms must be put into place to refine existing measures and establish new implementation measures to guide its growth.
The key to the future of marine aquaculture in the United State is the creation of technological and policy systems that provide for sustainable marine aquaculture. Systems that will move the industry forward will require an unequivocal commitment by the nation’s political leadership
to create them, by the federal bureaucracy to implement them, by the academic community to generate and extend information to improve them, and by the industry to put then into practice.
Cutworm species (Lepidoptera: Noctuidae) feeding on grapevines in the Okanagan Valley, British Columbia, with notes on rearing
Authors: Lowery D.T. , Mostafa A.M.
Published: April 2010

Eighteen species of cutworm moths were collected as larvae feeding at night on grapevines, Vitis sp. L. (Vitaceae), in south-central British Columbia, Canada, during April and May from 2004 to 2008. Ten species belonged to two genera, Abagrotis Smith and Euxoa Hübner. Abagrotis orbis (Grote), A. nefascia (Smith), and A. reedi Buckett accounted for over 85% of cutworms reared to adulthood. Abagrotis orbis and A. reedi were found in all locations; the former accounted for nearly 90% of larvae collected from vineyards on warm sandy soils. Abagrotis nefascia was largely restricted to cooler sites with heavier soils. For laboratory-reared A. orbis, pupal mass was highest and sex ratios were approximately equal when larvae were reared either on a pinto bean-based diet prepared with the recommended amount of water or on a commercial black cutworm diet and 50% of the recommended water. Survival to adult eclosion was significantly higher on the black cutworm diet, but because this was thicker than the pinto bean-based diet it was impractical to use. To date, A. orbis, A. nefascia, and A. reedi have been laboratory-reared continuously on artificial diet for more than six generations.
Trap response of cutworm moths (Abagrotis orbis) to a sex-attractant lure in grape vineyards
Authors: Landolt Peter J. , Lowery D. Thomas , Wright Lawrence C. , Smithhisler Constance , Gúedot Christelle , James David G.
Published: April 2010

Larvae of Abagrotis orbis (Grote) (Lepidoptera: Noctuidae) are climbing cutworms and can damage grapevines, Vitis vinifera L. (Vitaceae), in early spring by consuming expanding buds. A sex attractant would be useful for monitoring this insect in commercial vineyards. (Z)-7-Tetradecenyl acetate and (Z)-11-hexadecenyl acetate were found in extracts of female abdominal tips. In multiple field experiments, male A. orbis were captured in traps baited with a combination of these two chemicals but not in traps baited with either chemical alone. Males were trapped from mid-September to early October in south-central Washington and south-central British Columbia. Other noctuid moths (Mamestra configurata Walker, Xestia c-nigrum (L.), and Feltia jaculifera (Guenée)) were also captured in traps baited with the A. orbis pheromone and may complicate the use of this lure to monitor A. orbis. Abagrotis discoidalis (Grote) was captured in traps baited with (Z)-7-tetradecenyl acetate but not in traps baited with the two chemicals together.
The Role of the CCL2/CCR2 Axis in Mouse Mast Cell Migration In Vitro and In Vivo
Authors: Collington Sarah J. , Hallgren Jenny , Pease James E. , Jones Tatiana G. , Rollins Barrett J. , Westwick John , Austen K. Frank , Williams Timothy J. , Gurish Michael F. , Weller Charlotte L.
Published: April 2010

Tissue-resident mast cells (MCs) are important in allergic diseases. In a mouse model of allergic airways inflammation, an increase in peribronchiolar MCs was associated with increased concentrations of the chemokine CCL2 in lung lavage. MC progenitors (MCps) arising in bone marrow (BM) are recruited to tissues by transendothelial migration, and we found that CCL2 is chemotactic for MCps in freshly isolated BM in vitro. Immature, but not mature, BM-derived MCs migrated in response to CCL2 when cultured in IL-3+stem cell factor (SCF) but not when cultured in IL-3 alone. However, the cells under both culture conditions expressed mRNA for CCR2, the receptor for CCL2, and bound the radiolabeled chemokine with similar affinities, highlighting SCF as a key mediator in coupling CCR2 to downstream events, culminating in chemotaxis. Immature BM-derived MCs from IL-3 +SCF cultures, when administered i.v., accumulated at skin sites injected with CCL2 in vivo. MCp recruitment to the allergen-sensitized/challenged lung was significantly reduced in CCR2−/− and CCL2−/− mouse strains. However, reconstitution studies of sublethally irradiated and BM-reconstituted mice indicated that BM cells and stromal elements could provide CCL2, whereas the CCR2 function resided with stromal elements rather than BM cells. These experiments revealed a new function of SCF in chemokine receptor coupling, but they suggest a complex role of the CCL2/CCR2 axis in recruiting MCps during pulmonary inflammation.
Cutting Edge: Delay and Reversal of T Cell Tolerance by Intratumoral Injection of Antigen-Loaded Dendritic Cells in an Autochthonous Tumor Model
Authors: Higham Eileen M. , Shen Ching-Hung , Wittrup K. Dane , Chen Jianzhu
Published: April 2010

The tumor environment exerts a powerful suppressive influence on infiltrating tumor-reactive T cells. It induces tolerance of adoptively transferred effector T cells as they enter tumors and maintains the tolerance of persisting tumor-infiltrating T cells. In an autochthonous prostate cancer model, in which tumor-reactive CD8 T cells are trackable, we demonstrate that both depletion of endogenous dendritic cells (DCs) and intratumoral injection of Ag-loaded mature DCs delayed the tolerization of tumor-infiltrating effector CD8 T cells. Intratumoral injection of Ag-loaded DCs also reactivated tolerized CD8 T cells in the tumor tissue. The observed effects lasted as long as the injected DCs persisted. These findings are consistent with a critical role of DCs in modulating T cell reactivity in the tumor environment. They also suggest new potential strategies to extend the functionality of transferred effector T cells and to restore function to tolerized tumor-infiltrating T cells for cancer immunotherapy.
Novel Representation of Clinical Information in the ICU
Authors: Herasevich V. , Ahmed A. , Gajic O. , Pickering B.W.
Published: April 2010

The introduction of electronic medical records (EMR) and computerized physician order entry (CPOE) into the intensive care unit (ICU) is transforming the way health care providers currently work. The challenge facing developers of EMR’s is to create products which add value to systems of health care delivery. As EMR’s become more prevalent, the potential impact they have on the quality and safety, both negative and positive, will be amplified. In this paper we outline the key barriers to effective use of EMR and describe the methodology, using a worked example of the output. AWARE (Ambient Warning and Response Evaluation), is a physician led, electronic-environment enhancement program in an academic, tertiary care institution’s ICU. The development process is focused on reducing information overload, improving efficiency and eliminating medical error in the ICU.

Citation: Pickering BW, Herasevich V, Ahmed A, Gajic O. Novel representation of clinical information in the ICU – developing user interfaces which reduce information overload. Appl Clin Inf 2010; 1: 116–131 http://dx.doi.org/10.4338/ACI-2009-12-CR-0027
Lightning NOx emissions over the USA constrained by TES ozone observations and the GEOS-Chem model
Authors: Jourdain L. , Kulawik S. S. , Worden H. M. , Pickering K. E. , Worden J. , Thompson A. M.
Published: April 2010

Abstract. Improved estimates of NOx from lightning sources are required to understand tropospheric NOx and ozone distributions, the oxidising capacity of the troposphere and corresponding feedbacks between chemistry and climate change. In this paper, we report new satellite ozone observations from the Tropospheric Emission Spectrometer (TES) instrument that can be used to test and constrain the parameterization of the lightning source of NOx in global models. Using the National Lightning Detection (NLDN) and the Long Range Lightning Detection Network (LRLDN) data as well as the HYPSLIT transport and dispersion model, we show that TES provides direct observations of ozone enhanced layers downwind of convective events over the USA in July 2006. We find that the GEOS-Chem global chemistry-transport model with a parameterization based on cloud top height, scaled regionally and monthly to OTD/LIS (Optical Transient Detector/Lightning Imaging Sensor) climatology, captures the ozone enhancements seen by TES. We show that the model's ability to reproduce the location of the enhancements is due to the fact that this model reproduces the pattern of the convective events occurrence on a daily basis during the summer of 2006 over the USA, even though it does not well represent the relative distribution of lightning intensities. However, this model with a value of 6 Tg N/yr for the lightning source (i.e.: with a mean production of 260 moles NO/Flash over the USA in summer) underestimates the intensities of the ozone enhancements seen by TES. By imposing a production of 520 moles NO/Flash for lightning occurring in midlatitudes, which better agrees with the values proposed by the most recent studies, we decrease the bias between TES and GEOS-Chem ozone over the USA in July 2006 by 40%. However, our conclusion on the strength of the lightning source of NOx is limited by the fact that the contribution from the stratosphere is underestimated in the GEOS-Chem simulations.
Ice nucleation and cloud microphysical properties in tropical tropopause layer cirrus
Authors: Jensen E. J. , Pfister L. , Bui T.-P. , Lawson P. , Baumgardner D.
Published: April 2010

Abstract. In past modeling studies, it has generally been assumed that the predominant mechanism for nucleation of ice in the uppermost troposphere is homogeneous freezing of aqueous aerosols. However, recent in situ and remote-sensing measurements of the properties of cirrus clouds at very low temperatures in the tropical tropopause layer (TTL) are broadly inconsistent with theoretial predictions based on the homogeneous freezing assumption. The nearly ubiquitous occurence of gravity waves in the TTL makes the predictions from homogeneous nucleation theory particularly difficult to reconcile with measurements. These measured properties include ice number concentrations, which are much lower than theory predicts; ice crystal size distributions, which are much broader than theory predicts; and cloud extinctions, which are much lower than theory predicts. Although other explanations are possible, one way to limit ice concentrations is to have on the order of 50 L−1 effective ice nuclei (IN) that could nucleate ice at relatively low supersaturations. We suggest that ammonium sulfate particles, which would be dry much of the time in the cold TTL, are a potential IN candidate for TTL cirrus. However, this mechanism remains to be fully quantified for the size distribution of ammonium sulfate (possibly internally mixed with organics) actually present in the upper troposphere. Possible implications of the observed cloud microphysical properties for ice sedimentation, dehydration, and cloud persistence are also discussed.
Quantitative assessment of Southern Hemisphere ozone in chemistry-climate model simulations
Authors: Karpechko A. Yu. , Gillett N. P. , Hassler B. , Rosenlof K. H. , Rozanov E.
Published: April 2010

Abstract. Stratospheric ozone recovery in the Southern Hemisphere is expected to drive pronounced trends in atmospheric temperature and circulation from the stratosphere to the troposphere in the 21st century; therefore ozone changes need to be accounted for in future climate simulations. Many climate models do not have interactive ozone chemistry and rely on prescribed ozone fields, which may be obtained from coupled chemistry-climate model (CCM) simulations. However CCMs vary widely in their predictions of ozone evolution, complicating the selection of ozone boundary conditions for future climate simulations. In order to assess which models might be expected to better simulate future ozone evolution, and thus provide more realistic ozone boundary conditions, we assess the ability of twelve CCMs to simulate observed ozone climatology and trends and rank the models according to their errors averaged across the individual diagnostics chosen. According to our analysis no one model performs better than the others in all the diagnostics; however, combining errors in individual diagnostics into one metric of model performance allows us to objectively rank the models. The multi-model average shows better overall agreement with the observations than any individual model. Based on this analysis we conclude that the multi-model average ozone projection presents the best estimate of future ozone evolution and recommend it for use as a boundary condition in future climate simulations. Our results also demonstrate a sensitivity of the analysis to the choice of reference data set for vertical ozone distribution over the Antarctic, highlighting the constraints that large observational uncertainty imposes on such model verification.
Modelling the optical and radiative properties of freshly emitted light absorbing carbon within an atmospheric chemical transport model
Authors: Kahnert M.
Published: April 2010

Abstract. Light absorbing carbon (LAC) aerosols have a complex, fractal-like aggregate structure. Their optical and radiative properties are notoriously difficult to model, and approximate methods may introduce large errors both in the interpretation of aerosol remote sensing observations, and in quantifying the direct radiative forcing effect of LAC. In this paper a numerically exact method for solving Maxwell's equations is employed for computing the optical properties of freshly emitted, externally mixed LAC aggregates. The computations are performed at wavelengths of 440 nm and 870 nm, and they cover the entire size range relevant for modelling these kinds of aerosols. The method for solving the electromagnetic scattering and absorption problem for aggregates proves to be sufficiently stable and fast to make accurate multiple-band computations of LAC optical properties feasible. The results from the electromagnetic computations are processed such that they can readily be integrated into a chemical transport model (CTM), which is a prerequisite for constructing robust observation operators for chemical data assimilation of aerosol optical observations. A case study is performed, in which results obtained with the coupled optics/CTM model are employed as input to detailed radiative transfer computations at a polluted European location. It is found that the still popular homogeneous sphere approximation significantly underestimates the radiative forcing at top of atmosphere as compared to the results obtained with the aggregate model. Notably, the LAC forcing effect predicted with the aggregate model is less than that one obtains by assuming a prescribed mass absorption cross section for LAC.
Heterogeneous ozonation kinetics of 4-phenoxyphenol in the presence of photosensitizer
Authors: Net S. , Nieto-Gligorovski L. , Gligorovski S. , Wortham H.
Published: April 2010

Abstract. In this work we have quantitatively measured the degradation of 4-phenoxyphenol adsorbed on silica particles following oxidative processing by gas-phase ozone. This was performed under dark conditions and in the presence of 4-carboxybenzophenone under simulated sunlight irradiation of the particles surface. At the mixing ratio of 60 ppb which corresponds to strongly polluted ozone areas, the first order of decay of 4-phenoxyphenol is k1=9.95×10−6 s−1. At a very high ozone mixing ratio of 6 ppm the first order rate constants for 4-phenoxyphenol degradation were the following: k1=2.86×10−5 s−1 under dark conditions and k1=5.58×10−5 s−1 in the presence of photosensitizer (4-carboxybenzophenone) under light illumination of the particles surface. In both cases, the experimental data follow the modified Langmuir-Hinshelwood equation for surface reactions. The Langmuir-Hinshelwood and Langmuir-Rideal mechanisms for bimolecular surface reactions are also discussed along with the experimental results. Most importantly, the quantities of the oligomers such as 2-(4-Phenoxyphenoxy)-4-phenoxyphenol and 4-[4-(4-Phenoxyphenoxy)phenoxy]phenol formed during the heterogeneous ozonolysis of adsorbed 4-phenoxyphenol were much higher under solar light irradiation of the surface in comparison to the dark conditions.
Results from the CERN pilot CLOUD experiment
Authors: Duplissy J. , Enghoff M. B. , Aplin K. L. , Arnold F. , Aufmhoff H. , Avngaard M. , Baltensperger U. , Bondo T. , Bingham R. , Carslaw K. , Curtius J. , David A. , Fastrup B. , Gagné S. , Hahn F. , Harrison R. G. , Kellett B. , Kirkby J. , Kulmala M. , Laakso L. , Laaksonen A. , Lillestol E. , Lockwood M. , Mäkelä J. , Makhmutov V. , Marsh N. D. , Nieminen T. , Onnela A. , Pedersen E. , Pedersen J. O. P. , Polny J. , Reichl U. , Seinfeld J. H. , Sipilä M. , Stozhkov Y. , Stratmann F. , Svensmark H. , Svensmark J. , Veenhof R. , Verheggen B. , Viisanen Y. , Wagner P. E. , Wehrle G. , Weingartner E. , Wex H. , Wilhelmsson M. , Winkler P. M.
Published: April 2010

Abstract. During a 4-week run in October–November 2006, a pilot experiment was performed at the CERN Proton Synchrotron in preparation for the Cosmics Leaving OUtdoor Droplets (CLOUD) experiment, whose aim is to study the possible influence of cosmic rays on clouds. The purpose of the pilot experiment was firstly to carry out exploratory measurements of the effect of ionising particle radiation on aerosol formation from trace H2SO4 vapour and secondly to provide technical input for the CLOUD design. A total of 44 nucleation bursts were produced and recorded, with formation rates of particles above the 3 nm detection threshold of between 0.1 and 100 cm−3s−1, and growth rates between 2 and 37 nm h−1. The corresponding H2O concentrations were typically around 106 cm−3 or less. The experimentally-measured formation rates and H2SO4 concentrations are comparable to those found in the atmosphere, supporting the idea that sulphuric acid is involved in the nucleation of atmospheric aerosols. However, sulphuric acid alone is not able to explain the observed rapid growth rates, which suggests the presence of additional trace vapours in the aerosol chamber, whose identity is unknown. By analysing the charged fraction, a few of the aerosol bursts appear to have a contribution from ion-induced nucleation and ion-ion recombination to form neutral clusters. Some indications were also found for the accelerator beam timing and intensity to influence the aerosol particle formation rate at the highest experimental SO2 concentrations of 6 ppb, although none was found at lower concentrations. Overall, the exploratory measurements provide suggestive evidence for ion-induced nucleation or ion-ion recombination as sources of aerosol particles. However in order to quantify the conditions under which ion processes become significant, improvements are needed in controlling the experimental variables and in the reproducibility of the experiments. Finally, concerning technical aspects, the most important lessons for the CLOUD design include the stringent requirement of internal cleanliness of the aerosol chamber, as well as maintenance of extremely stable temperatures (variations below 0.1 °C
Evaluation of Arctic cloud products from the EUMETSAT Climate Monitoring Satellite Application Facility based on CALIPSO-CALIOP observations
Authors: Karlsson K.-G. , Dybbroe A.
Published: April 2010

Abstract. The performance of the three cloud products cloud fractional cover, cloud type and cloud top height, derived from NOAA AVHRR data and produced by the EUMETSAT Climate Monitoring Satellite Application Facility, has been evaluated in detail over the Arctic region for four months in 2007 using CALIPSO-CALIOP observations. The evaluation was based on 142 selected NOAA/Metop overpasses allowing almost 400 000 individual matchups between AVHRR pixels and CALIOP measurements distributed approximately equally over the studied months (June, July, August and December 2007). Results suggest that estimations of cloud amounts are very accurate during the polar summer season while a substantial loss of detected clouds occurs in the polar winter. Evaluation results for cloud type and cloud top products point at specific problems related to the existence of near isothermal conditions in the lower troposphere in the polar summer and the use of reference vertical temperature profiles from Numerical Weather Prediction model analyses. The latter are currently not detailed enough in describing true conditions relevant on the pixel scale. This concerns especially the description of near-surface temperature inversions which are often too weak leading to large errors in interpreted cloud top heights.
Sample drying to improve HCHO measurements by PTR-MS instruments: laboratory and field measurements
Authors: Jobson B. T. , McCoskey J. K.
Published: April 2010

Abstract. A significant improvement in the PTR-MS instrument sensitivity to formaldehyde was obtained by drying the air sample to a dew point of −30 °C using a cold trap to condense and freeze water vapour. At warmer trap temperatures there was significant uptake of formaldehyde and other water soluble organics, suggesting the presence of a quasi-liquid layer on the ice surface. By removing water vapour to a low constant dew point, the PTR-MS can be operated at low E/N ratios, significantly increasing normalized sensitivities for all organics and removing their humidity dependence due to reactions with H+(H2O)2. At an E/N ratio of 80 Td, the formaldehyde normalized sensitivity was 25 Hz/ppbv per MHz H3O+ with an estimated detection limit of 78 pptv. Field testing demonstrated good agreement between HCHO measurements made at ambient humidity and corrected for water vapour effects compared to dehumidified sampling at −30 °C. Field testing also revealed that at an E/N ratio of 100 Td or lower there was a significant ion signal at m/z=49, likely CH3OOH. Sampling drying and operation at low E/N ratios enables sensitive measurements of HCHO and potentially CH3OOH, both important tropospheric photoproducts.
Comparison of aromatic hydrocarbon measurements made by PTR-MS, DOAS and GC-FID during the MCMA 2003 Field Experiment
Authors: Jobson B. T. , Volkamer R. A. , Velasco E. , Allwine G. , Westberg H. , Lamb B. K. , Alexander M. L. , Berkowitz C. M. , Molina L. T.
Published: April 2010

Abstract. A comparison of aromatic hydrocarbon measurements is reported for the CENICA supersite in the district of Iztapalapa during the Mexico City Metropolitan Area field experiment in April 2003 (MCMA 2003). Data from three different measurement methods were compared: a Proton Transfer Reaction Mass Spectrometer (PTR-MS), long path measurements using a UV Differential Optical Absorption Spectrometer (DOAS), and Gas Chromatography-Flame Ionization analysis (GC-FID) of canister samples. The principle focus was on the comparison between PTR-MS and DOAS data. Lab tests established that the PTR-MS and DOAS calibrations were consistent for a suite of aromatic compounds including benzene, toluene, p-xylene, ethylbenzene, 1,2,4-trimethylbenzene, phenol and styrene. The point sampling measurements by the PTR-MS and GC-FID showed good correlations (r=0.6), and were in reasonable agreement for toluene, C2-alkylbenzenes and C3-alkylbenzenes. The PTR-MS benzene data were consistently high, indicating interference from ethylbenzene fragmentation for the 145 Td drift field intensity used in the experiment. Correlations between the open-path data measured at 16-m height over a 860-m path length (retroreflector in 430 m distance), and the point measurements collected at 37-m sampling height were best for benzene (r=0.61), and reasonably good for toluene, C2-alkylbenzenes, naphthalene, styrene, cresols and phenol (r>0.5). There was good agreement between DOAS and PTR-MS measurements of benzene after correction for the PTR-MS ethylbenzene interference. Mixing ratios measured by DOAS were on average a factor of 1.7 times greater than the PTR-MS data for toluene, C2-alkylbenzenes, naphthalene and styrene. The level of agreement for the toluene data displayed a modest dependence on wind direction, establishing that spatial gradients – horizontal, vertical, or both – in toluene mixing ratios were significant, and up to a factor of 2 despite the fact that all measurements were conducted above roof level. Our analysis highlights a potential problem in defining a VOC sampling strategy that is meaningful for the comparison with photochemical transport models: meaningful measurements require a spatial fetch that is comparable to the grid cell size of models, which is typically a few 10 km2. Long-path DOAS measurements inherently average over a larger spatial scale than point measurements. The spatial representativeness can be further increased if observations are conducted outside the surface roughness sublayer, which might require measurements at altitudes as high as 10 s of metres above roof level.
Trend in ice moistening the stratosphere – constraints from isotope data of water and methane
Authors: Notholt J. , Toon G. C. , Fueglistaler S. , Wennberg P. O. , Irion F. W. , McCarthy M. , Scharringhausen M. , Siek Rhee T. , Kleinböhl A. , Velazco V.
Published: April 2010

Abstract. Water plays a major role in the chemistry and radiative budget of the stratosphere. Air enters the stratosphere predominantly in the tropics, where the very low temperatures around the tropopause constrain water vapour mixing ratios to a few parts per million. Observations of stratospheric water vapour show a large positive long-term trend, which can not be explained by change in tropopause temperatures. Trends in the partitioning between vapour and ice of water entering the stratosphere have been suggested to resolve this conundrum. We present measurements of stratospheric H2O, HDO, CH4 and CH3D in the period 1991–2007 to evaluate this hypothesis. Because of fractionation processes during phase changes, the hydrogen isotopic composition of H2O is a sensitive indicator of changes in the partitioning of vapour and ice. We find that the seasonal variations of H2O are mirrored in the variation of the ratio of HDO to H2O with a slope of the correlation consistent with water entering the stratosphere mainly as vapour. The variability in the fractionation over the entire observation period is well explained by variations in H2O. The isotopic data allow concluding that the trend in ice arising from particulate water is no more than (0.01±0.13) ppmv/decade in the observation period. Our observations suggest that between 1991 and 2007 the contribution from changes in particulate water transported through the tropopause plays only a minor role in altering in the amount of water entering the stratosphere.
Black carbon over Mexico: the effect of atmospheric transport on mixing state, mass absorption cross-section, and BC/CO ratios
Authors: Subramanian R. , Kok G. L. , Baumgardner D. , Clarke A. , Shinozuka Y. , Campos T. L. , Heizer C. G. , Stephens B. B. , de Foy B. , Voss P. B. , Zaveri R. A.
Published: April 2010

Abstract. A single particle soot photometer (SP2) was operated on the NCAR C-130 during the MIRAGE campaign (part of MILAGRO), sampling black carbon (BC) over Mexico. The highest BC concentrations were measured over Mexico City (sometimes as much as 2 μg/m3) and over hill-fires to the south of the city. The age of plumes outside of Mexico City was determined using a combination of HYSPLIT trajectories, WRF-FLEXPART modeling and CMET balloon tracks. As expected, older, diluted air masses had lower BC concentrations. A comparison of carbon monoxide (CO) and BC suggests a CO background of around 65 ppbv, and a background-corrected BC/COnet ratio of 2.89±0.89 (ng/m3-STP)/ppbv (average ± standard deviation). This ratio is similar for fresh emissions over Mexico City, as well as for aged airmasses. Comparison of light absorption measured with a particle soot absorption photometer (PSAP) and the SP2 BC suggests a BC mass-normalized absorption cross-section (MAC) of 10.9±2.1 m2/g at 660 nm (or 13.1 m2/g @ 550 nm, assuming MAC is inversely dependent on wavelength). This appears independent of aging and similar to the expected absorption cross-section for aged BC, but values, particularly in fresh emissions, could be biased high due to instrument artifacts. SP2-derived BC coating indicators show a prominent thinly-coated BC mode over the Mexico City Metropolitan Area (MCMA), while older air masses show both thinly-coated and thickly-coated BC. Some 2-day-old plumes do not show a prominent thickly-coated BC mode, possibly due to preferential wet scavenging of the likely-hydrophilic thickly-coated BC.
An introduction to the SCOUT-AMMA stratospheric aircraft, balloons and sondes campaign in West Africa, August 2006: rationale and roadmap
Authors: Cairo F. , Pommereau J. P. , Law K. S. , Schlager H. , Garnier A. , Fierli F. , Ern M. , Streibel M. , Arabas S. , Borrmann S. , Berthelier J. J. , Blom C. , Christensen T. , D'Amato F. , Di Donfrancesco G. , Deshler T. , Diedhiou A. , Durry G. , Engelsen O. , Goutail F. , Harris N. R. P. , Kerstel E. R. T. , Khaykin S. , Konopka P. , Kylling A. , Larsen N. , Lebel T. , Liu X. , MacKenzie A. R. , Nielsen J. , Oulanowski A. , Parker D. J. , Pelon J. , Polcher J. , Pyle J. A. , Ravegnani F. , Rivière E. D. , Robinson A. D. , Röckmann T. , Schiller C. , Simões F. , Stefanutti L. , Stroh F. , Some L. , Siegmund P. , Sitnikov N. , Vernier J. P. , Volk C. M. , Voigt C. , von Hobe M. , Viciani S. , Yushkov V.
Published: April 2010

Abstract. A multi-platform field measurement campaign involving aircraft and balloons took place over West Africa between 26 July and 25 August 2006, in the frame of the concomitant AMMA Special Observing Period and SCOUT-O3 African tropical activities. Specifically aiming at sampling the upper troposphere and lower stratosphere, the high-altitude research aircraft M55 Geophysica was deployed in Ouagadougou (12.3° N, 1.7° W), Burkina Faso, in conjunction with the German D-20 Falcon, while a series of stratospheric balloons and sonde flights were conducted from Niamey (13.5° N, 2.0° E), Niger. Altogether, these measurements were intended to provide experimental evidence for a better understanding of large scale transport, assessing the effect of lightning on NOx production, and studying the impact of intense mesoscale convective systems on water, aerosol, dust and chemical species in the upper troposphere and lower stratosphere. The M55 Geophysica carried out five local and four transfer flights between southern Europe and the Sahel and back, while eight stratospheric balloons and twenty-nine sondes were flown from Niamey. These experiments allowed a characterization of the tropopause and lower stratosphere of the region. The paper provides an overview of SCOUT-AMMA campaign activities together with a description of the meteorology of the African monsoon and the situation prevailing during the flights and a brief summary of the observations accomplished.
Statistical properties of aerosol-cloud-precipitation interactions in South America
Authors: Jones T. A. , Christopher S. A.
Published: April 2010

Abstract. Given the complex interaction between aerosol, cloud, and atmospheric properties, it is difficult to extract their individual effects to observed rainfall amount. This research uses principle component analysis (PCA) that combines Moderate Resolution Imaging Spectroradiometer (MODIS) aerosol and cloud products, NCEP Reanalysis atmospheric products, and rainrate estimates from the Tropical Rainfall Measuring Mission (TRMM) precipitation radar (PR) to assess if aerosols affect warm rain processes. Data collected during September 2006 over the Amazon basin in South America during the biomass-burning season are used. The goal of this research is to combine these observations into a smaller number of variables through PCA with each new variable having a unique physical interpretation. In particular, we are concerned with PC variables whose weightings include aerosol optical thickness (AOT), as these may be an indicator of aerosol indirect effects. If they are indeed occurring, then PC values that include AOT should change as a function of rainrate. To emphasize the advantage of PCA, changes in aerosol, cloud, and atmospheric observations are compared to rainrate. Comparing no-rain, rain, and heavy rain only (>5 mm h−1) samples, we find that cloud thicknesses, humidity, and upward motion are all greater during rain and heavy rain conditions. However, no statistically significant difference in AOT exists between each sample, indicating that atmospheric conditions are more important to rainfall than aerosol concentrations as expected. If aerosols are affecting warm process clouds, it would be expected that stratiform precipitation would decrease as a function increasing aerosol concentration through either Twomey and/or semi-direct effects. PCA extracts the latter signal in a variable labeled PC2, which explains 15% of the total variance and is second in importance the variable (PC1) containing the broad atmospheric conditions. PC2 contains weightings showing that AOT is inversely proportional to low-level humidity and cloud optical thickness. Increasing AOT is also positively correlated with increasing low-level instability due to aerosol absorption. The nature of these weightings is strongly suggestive that PC2 is an indicator of the semi-direct effect with larger values associated with lower rainfall rates. PC weightings consistent with the Twomey effect (an anti-correlation between AOT and cloud droplet effective radius) are only present in higher order PC variables that explain less than 1% of the total variance, and do not vary significantly as a function of rainrate. If the Twomey effect is occurring, it is highly non-linear and/or being overshadowed by other processes. Using the raw variables alone, these determinations could not be made; thus, we are able to show the advantage of using advanced statistical techniques such as PCA for analysis of aerosols impacts on precipitation in South America.
On the transitions in marine boundary layer cloudiness
Authors: Sandu I. , Stevens B. , Pincus R.
Published: April 2010

Abstract. Satellite observations and meteorological reanalysis are used to examine the transition from unbroken sheets of stratocumulus to fields of scattered cumulus, and the processes controlling them, in four subtropical oceans. A Lagrangian analysis suggests that both the transition, defined as the temporal evolution in cloudiness, and the processes driving the transition, are quite similar among the subtropical oceans. The increase in sea surface temperature and the associated decrease in lower tropospheric stability appear to play a far more important role in cloud evolution than other factors including changes in large scale divergence and upper tropospheric humidity. During the summer months, the transitions in marine boundary layer cloudiness appear so systematically that their characteristics obtained by documenting the flow of thousands of individual air masses are well reproduced by the mean (or climatological) fields of the different data sets. This highlights interesting opportunities for future observational and modeling studies of these transitions.
Physical and optical properties of aerosols over an urban location in Spain: seasonal and diurnal variability
Authors: Lyamani H. , Olmo F. J. , Alados-Arboledas L.
Published: April 2010

Abstract. Measurements of aerosol optical properties and aerosol number size distribution obtained during the period from December 2005 to November 2007 at Granada, an urban site in south-eastern Spain, are analyzed. Large variations of the measured variables have been found, and related to variations in emissions sources and meteorological conditions. High values of aerosol absorption and scattering coefficients are obtained during winter and low values are measured during summer. This seasonal pattern in the surface aerosol optical properties is opposite to the seasonal cycle showed by columnar aerosol optical depth. The differences in the seasonal features of the surface and column-integrated data are related to seasonal variations in the aerosol vertical distribution, aerosol sources and boundary layer height. In winter the number density of "fine" particles (0.5<particle diameter<1 μm) is significantly larger than in summer while the number density of "coarse" particles (1<particle diameter<20 μm) is slightly larger during summer and spring than during winter and autumn. The scattering Angström exponent, αs, presents an evident seasonal cycle with values of 1.8±0.2, 1.6±0.3, 1.3±0.3 and 1.4±0.3 in winter, spring, summer and autumn, respectively. This suggests the presence of a large fraction of submicron particles at the site, especially during winter. The aerosols measured in this study contain a large fraction of absorbing material as indicated by the average single-scattering albedo that has values of 0.65±0.07, 0.66±0.06, 0.70±0.06 and 0.73±0.06 in autumn, winter, spring and summer, respectively. The aerosol scattering albedo obtained in the surface boundary layer of Granada is below the critical value of 0.86 that determines the shift from cooling to warming. These results put in evidence the need of efforts to reduce absorbing particles (black carbon) emissions to avoid the possible warming that would result from the reductions of the cooling aerosols only. The aerosol absorption and scattering coefficients present a clear diurnal pattern, in all seasons, with two local maxima, one early in the morning and the second one in the evening. This diurnal cycle is mainly attributed to the diurnal evolution of atmospheric boundary layer and local anthropogenic activities.
Atmospheric gaseous elemental mercury (GEM) concentrations and mercury depositions at a high-altitude mountain peak in south China
Authors: Fu X. W. , Feng X. , Dong Z. Q. , Yin R. S. , Wang J. X. , Yang Z. R. , Zhang H.
Published: April 2010

Abstract. China is regarded as the largest contributor of mercury (Hg) to the global atmospheric Hg budget. However, concentration levels and depositions of atmospheric Hg in China are poorly known. Continuous measurements of atmospheric gaseous elemental mercury (GEM) were carried out from May 2008 to May 2009 at the summit of Mt. Leigong in south China. Simultaneously, deposition fluxes of THg and MeHg in precipitation, throughfall and litterfall were also studied. Atmospheric GEM concentrations averaged 2.80±1.51 ng m−3, which was highly elevated compared to global background values but much lower than semi-rural and industrial/urban areas in China. Sources identification indicates that both regional industrial emissions and long range transport of Hg from central, south and southwest China were corresponded to the elevated GEM level. Seasonal and diurnal variations of GEM were observed, which reflected variations in source intensity, deposition processes and meteorological factors. Precipitation and throughfall deposition fluxes of THg and MeHg in Mt. Leigong were comparable or lower compared to those reported in Europe and North America, whereas litterfall deposition fluxes of THg and MeHg were higher compared to Europe and North America. This highlights the importance of vegetation to Hg atmospheric cycling. In th remote forest ecosystem of China, deposition of GEM via uptake of foliage followed by litterfall was very important for the depletion of atmospheric Hg. Elevated GEM level in ambient air may accelerate the foliar uptake of Hg through air which may partly explain the elevated litterfall deposition fluxes of Hg observed in Mt. Leigong.
High-accuracy measurements of snow Bidirectional Reflectance Distribution Function at visible and NIR wavelengths – comparison with modelling results
Authors: Dumont M. , Brissaud O. , Picard G. , Schmitt B. , Gallet J.-C. , Arnaud Y.
Published: April 2010

Abstract. High-accuracy measurements of snow Bidirectional Reflectance Distribution Function (BRDF) were performed for four natural snow samples with a spectrogonio-radiometer in the 500–2600 nm wavelength range. These measurements are one of the first sets of direct snow BRDF values over a wide range of lighting and viewing geometry. They were compared to BRDF calculated with two optical models. Variations of the snow anisotropy factor with lighting geometry, wavelength and snow physical properties were investigated. Results show that at wavelengths with small penetration depth, scattering mainly occurs in the very top layers and the anisotropy factor is controlled by the phase function. In this condition, forward scattering peak or double scattering peak is observed. In contrast at shorter wavelengths, the penetration of the radiation is much deeper and the number of scattering events increases. The anisotropy factor is thus nearly constant and decreases at grazing observation angles. The whole dataset is available on demand from the corresponding author.
Applying an ensemble Kalman filter to the assimilation of AERONET observations in a global aerosol transport model
Authors: Schutgens N. A. J. , Miyoshi T. , Takemura T. , Nakajima T.
Published: April 2010

Abstract. We present a global aerosol assimilation system based on an Ensemble Kalman filter, which we believe leads to a significant improvement in aerosol fields. The ensemble allows realistic, spatially and temporally variable model covariances (unlike other assimilation schemes). As the analyzed variables are mixing ratios (prognostic variables of the aerosol transport model), there is no need for the extra assumptions required by previous assimilation schemes analyzing aerosol optical thickness (AOT). We describe the implementation of this assimilation system and in particular the construction of the ensemble. This ensemble should represent our estimate of current model uncertainties. Consequently, we construct the ensemble around randomly modified emission scenarios. The system is tested with AERONET observations of AOT and Angström exponent (AE). Particular care is taken in prescribing the observational errors. The assimilated fields (AOT and AE) are validated through independent AERONET, SKYNET and MODIS Aqua observations. We show that, in general, assimilation of AOT observations leads to improved modelling of global AOT, while assimilation of AE only improves modelling when the AOT is high.