bluuebunny/crossref_metadata_2025 huggingface dataset:
Life Participation for Parents: A Tool for Family-Centered Occupational Therapy
Authors: Fingerhut Patricia E.
Published: December 2012

OBJECTIVE. This study describes the continued development of the Life Participation for Parents (LPP), a measurement tool to facilitate family-centered pediatric practice.

METHOD. LPP questionnaires were completed by 162 parents of children with special needs receiving intervention at 15 pediatric private practice clinics. Results were analyzed to establish instrument reliability and validity.

RESULTS. Good internal consistency (α = .90) and test–retest reliability (r = .89) were established. Construct validity was examined through assessment of internal structure and comparison of the instrument to related variables. A principal components analysis resulted in a two-factor model accounting for 43.81% of the variance. As hypothesized, the LPP correlated only moderately with the Parenting Stress Index–Short Form (r = .54). The variables of child’s diagnoses, age, and time in therapy did not predict parental responses.

CONCLUSION. The LPP is a reliable and valid instrument for measuring satisfaction with parental participation in life occupations.
Assessing Handwriting Intervention Effectiveness in Elementary School Students: A Two-Group Controlled Study
Authors: Howe Tsu-Hsin , Roston Karen Laurie , Sheu Ching-Fan , Hinojosa Jim
Published: December 2012

This study examined the effectiveness of two approaches used in elementary schools to improve children’s handwriting. Participants were 72 New York City public school students from the first and second grades. A nonequivalent pretest–posttest group design was used in which students engaged in handwriting activities using two approaches: intensive handwriting practice and visual–perceptual–motor activities. Handwriting speed, legibility, and visual–motor skills were examined after a 12-wk Handwriting Club using multivariate analysis of variance. The results showed that students in the intensive handwriting practice group demonstrated significant improvements in handwriting legibility compared with students in the visual–perceptual–motor activity group. No significant effects in handwriting speed and visual–motor skills were found between the students in intensive handwriting practice group and the students in visual–perceptual–motor activities group. The Handwriting Club model is a natural intervention that fits easily into existing school curriculums and can be an effective short-term intervention (response to intervention Tier II).
Effectiveness of a Physical Activity Intervention for Head Start Preschoolers: A Randomized Intervention Study
Authors: Bellows Laura L. , Davies Patricia L. , Anderson Jennifer , Kennedy Catherine
Published: December 2012

OBJECTIVES. The level of children’s motor skill proficiency may be an important determinant of their physical activity behaviors. This study assessed the efficacy of an intervention on gross motor skill performance, physical activity, and weight status of preschoolers.

METHOD. The Food Friends: Get Movin’ With Mighty Moves® program was conducted in four Head Start centers. Measurements included the Peabody Developmental Motor Scales, pedometer counts, and body mass index (BMI) z scores.

RESULTS. The intervention led to significant changes in gross motor skills in the treatment group (n = 98) compared with the control group (n = 103) and was a strong predictor of overall gross motor performance (gross motor quotient), locomotor, stability, and object manipulation skills. No intervention effect was found for physical activity levels or weight status.

CONCLUSION. The intervention dose was adequate for enhancing gross motor skill performance but not for increasing physical activity levels or reducing BMI.
Reliability of the Health Enhancement Lifestyle Profile–Screener (HELP–Screener)
Authors: Hwang Jengliang Eric
Published: December 2012

This study examined reliability of the Health Enhancement Lifestyle Profile–Screener (HELP–Screener), a 15-item self-report questionnaire serving as an initial screening of lifestyle behaviors for older adults. The internal consistency of HELP–Screener was analyzed using data derived from a sample of 483 older adults. The resultant Cronbach’s α coefficient of .74 indicated an acceptable level of internal consistency. The test–retest reliability study with 90 participants yielded an intraclass correlation coefficient of .93, indicating a high degree of temporal stability of the instrument at the scale level. Moreover, good to excellent degrees of agreement found through the κ statistic (ks = .76–.96) and percentage of agreement (96%–99%) between the test and retest scores of each item further supported HELP–Screener’s test–retest reliability at the item level. Future studies should determine other aspects of psychometric properties and clinical suitability of this new instrument.
Climate versus emission drivers of methane lifetime against loss by tropospheric OH from 1860–2100
Authors: John J. G. , Fiore A.  M. , Naik V. , Horowitz L.  W. , Dunne J. P.
Published: December 2012

Abstract. With a more-than-doubling in the atmospheric abundance of the potent greenhouse gas methane (CH4) since preindustrial times, and indications of renewed growth following a leveling off in recent years, questions arise as to future trends and resulting climate and public health impacts from continued growth without mitigation. Changes in atmospheric methane lifetime are determined by factors which regulate the abundance of OH, the primary methane removal mechanism, including changes in CH4 itself. We investigate the role of emissions of short-lived species and climate in determining the evolution of methane lifetime against loss by tropospheric OH, (τCH4_OH), in a suite of historical (1860–2005) and future Representative Concentration Pathway (RCP) simulations (2006–2100), conducted with the Geophysical Fluid Dynamics Laboratory (GFDL) fully coupled chemistry-climate model (CM3). From preindustrial to present, CM3 simulates an overall 5% increase in τCH4_OH due to a doubling of the methane burden which offsets coincident increases in nitrogen oxide (NOx emissions. Over the last two decades, however, the τCH4_OH declines steadily, coinciding with the most rapid climate warming and observed slow-down in CH4 growth rates, reflecting a possible negative feedback through the CH4 sink. Sensitivity simulations with CM3 suggest that the aerosol indirect effect (aerosol-cloud interactions) plays a significant role in cooling the CM3 climate. The projected decline in aerosols under all RCPs contributes to climate warming over the 21st century, which influences the future evolution of OH concentration and τCH4_OH. Projected changes in τCH4_OH from 2006 to 2100 range from −13% to +4%. The only projected increase occurs in the most extreme warming case (RCP8.5) due to the near-doubling of the CH4 abundance, reflecting a positive feedback on the climate system. The largest decrease occurs in the RCP4.5 scenario due to changes in short-lived climate forcing agents which reinforce climate warming and enhance OH. This decrease is more-than-halved in a sensitivity simulation in which only well-mixed greenhouse gas radiative forcing changes along the RCP4.5 scenario (5% vs. 13%).
Cloud condensation nuclei production associated with atmospheric nucleation: a synthesis based on existing literature and new results
Authors: Kerminen V.-M. , Paramonov M. , Anttila T. , Riipinen I. , Fountoukis C. , Korhonen H. , Asmi E. , Laakso L. , Lihavainen H. , Swietlicki E. , Svenningsson B. , Asmi A. , Pandis S. N. , Kulmala M. , Petäjä T.
Published: December 2012

Abstract. This paper synthesizes the available scientific information connecting atmospheric nucleation with subsequent cloud condensation nuclei (CCN) formation. We review both observations and model studies related to this topic, and discuss the potential climatic implications. We conclude that CCN production associated with atmospheric nucleation is both frequent and widespread phenomenon in many types of continental boundary layers, and probably also over a large fraction of the free troposphere. The contribution of nucleation to the global CCN budget spans a relatively large uncertainty range, which, together with our poor understanding of aerosol-cloud interactions, results in major uncertainties in the radiative forcing by atmospheric aerosols. In order to better quantify the role of atmospheric nucleation in CCN formation and Earth System behavior, more information is needed on (i) the factors controlling atmospheric CCN production and (ii) the properties of both primary and secondary CCN and their interconnections. In future investigations, more emphasis should be put on combining field measurements with regional and large-scale model studies.
Sensitivity studies of dust ice nuclei effect on cirrus clouds with the Community Atmosphere Model CAM5
Authors: Liu X. , Shi X. , Zhang K. , Jensen E. J. , Gettelman A. , Barahona D. , Nenes A. , Lawson P.
Published: December 2012

Abstract. In this study the effect of dust aerosol on upper tropospheric cirrus clouds through heterogeneous ice nucleation is investigated in the Community Atmospheric Model version 5 (CAM5) with two ice nucleation parameterizations. Both parameterizations consider homogeneous and heterogeneous nucleation and the competition between the two mechanisms in cirrus clouds, but differ significantly in the number concentration of heterogeneous ice nuclei (IN) from dust. Heterogeneous nucleation on dust aerosol reduces the occurrence frequency of homogeneous nucleation and thus the ice crystal number concentration in the Northern Hemisphere (NH) cirrus clouds compared to simulations with pure homogeneous nucleation. Global and annual mean shortwave and longwave cloud forcing are reduced by up to 2.0 ± 0.1 W m−2 (1σ uncertainty) and 2.4 ± 0.1 W m−2, respectively due to the presence of dust IN, with the net cloud forcing change of −0.40 ± 0.20 W m−2. Comparison of model simulations with in situ aircraft data obtained in NH mid-latitudes suggests that homogeneous ice nucleation may play an important role in the ice nucleation at these regions with temperatures of 205–230 K. However, simulations overestimate observed ice crystal number concentrations in the tropical tropopause regions with temperatures of 190–205 K, and overestimate the frequency of occurrence of high ice crystal number concentration (> 200 L−1) and underestimate the frequency of low ice crystal number concentration (< 30 L−1) at NH mid-latitudes. These results highlight the importance of quantifying the number concentrations and properties of heterogeneous IN (including dust aerosol) in the upper troposphere from the global perspective.
Comparison between summertime and wintertime Arctic Ocean primary marine aerosol properties
Authors: Zábori J. , Krejci R. , Ström J. , Vaattovaara P. , Ekman A. M. L. , Mårtensson E. M. , Nilsson E. D.
Published: December 2012

Abstract. Primary marine aerosols (PMA) are an important source of cloud condensation nuclei, and one of the key elements of the remote marine radiative budget. Changes occurring in the rapidly warming Arctic, most importantly the decreasing sea ice extent will alter PMA production and hence the Arctic climate through a set of feedback processes. In light of this, laboratory experiments with Arctic Ocean water during both Arctic winter and summer were conducted and focused on PMA emissions as a function of season and water properties. Total particle number concentrations and particle number size distributions were used to characterize the PMA population. A comprehensive data set from the Arctic summer and winter showed a decrease in PMA concentrations for the covered water temperature (Tw) range between −1 °C and 15 °C. A sharp decrease in PMA emissions for a Tw increase from −1 °C to 4 °C was followed by a lower rate of change in PMA emissions for Tw up to about 6 °C. Near constant number concentrations for water temperatures between 6 °C to 10 °C and higher were recorded. Even though the total particle number concentrations changes for overlapping Tw ranges were consistent between the summer and winter measurements, the distribution of particle number concentrations among the different sizes varied between the seasons. Median particle number concentrations for Dp < 0.125 μm measured during winter conditions were similar (deviation of up to 3%), or lower (up to 70%) than the ones measured during summer conditions (for the same water temperature range). For Dp > 0.125 μm, the particle number concentrations during winter were mostly higher than in summer (up to 50%). The normalized particle number size distribution as a function of water temperature was examined for both winter and summer measurements. An increase in Tw from −1 °C to 10 °C during winter measurements showed a decrease in the peak of relative particle number concentration at about Dp of 0.180 μm, while an increase was observed for particles with Dp > 1 μm. Summer measurements exhibited a relative shift to smaller particle sizes for an increase of Tw in the range 7–11 °C. The differences in the shape of the number size distributions between winter and summer may be caused by different production of organic material in water, different local processes modifying the water masses within the fjord (like sea ice production in winter and increased glacial melt water inflow during summer) and different origin of the dominant sea water mass. Further research is needed regarding the contribution of these factors to the PMA production.
Volcanic SO2 fluxes derived from satellite data: a survey using OMI, GOME-2, IASI and MODIS
Authors: Theys N. , Campion R. , Clarisse L. , Brenot H. , van Gent J. , Dils B. , Corradini S. , Merucci L. , Coheur P.-F. , Van Roozendael M. , Hurtmans D. , Clerbaux C. , Tait S. , Ferrucci F.
Published: December 2012

Abstract. Sulphur dioxide (SO2) fluxes of active degassing volcanoes are routinely measured with ground-based equipment to characterize and monitor volcanic activity. SO2 of unmonitored volcanoes or from explosive volcanic eruptions, can be measured with satellites. However, remote-sensing methods based on absorption spectroscopy generally provide integrated amounts of already dispersed plumes of SO2 and satellite derived flux estimates are rarely reported. Here we review a number of different techniques to derive volcanic SO2 fluxes using satellite measurements of dispersed and large-scale plumes of SO2 and investigate the temporal evolution of the total emissions of SO2 for three very different volcanic events in 2011: Puyehue-Cordón Caulle (Chile), Nyamulagira (DR Congo) and Nabro (Eritrea). High spectral resolution satellite instruments operating both in the UV-visible (OMI/Aura and GOME-2/MetOp-A) and thermal infrared (IASI/MetOp-A) spectral ranges, and multispectral satellite instruments operating in the thermal infrared (MODIS/Terra-Aqua) are used. We show that satellite data can provide fluxes with a sampling of a day or less (few hours in the best case). Generally the flux results from the different methods are consistent, and we discuss the advantages and weaknesses of each technique. Although the primary objective of this study is the calculation of SO2 fluxes, it also enables to assess the consistency of the SO2 products from the different sensors used.
Exceptional emissions of NH3 and HCOOH in the 2010 Russian wildfires
Authors: R'Honi Y. , Clarisse L. , Clerbaux C. , Hurtmans D. , Duflot V. , Turquety S. , Ngadi Y. , Coheur P.-F.
Published: December 2012

Abstract. In July 2010, several hundred forest and peat fires broke out across Central Russia during its hottest summer on record. Here, we analyze these wildfires using observations of the Infrared Atmospheric Sounding Interferometer (IASI). Carbon monoxide (CO), ammonia (NH3) and formic acid (HCOOH) total columns are presented for the year 2010. Maximum total columns have been observed reaching over 40 (for CO and HCOOH) and 200 (for NH3) times higher than typical background values. The temporal evolution of NH3 and HCOOH enhancement ratios relative to CO are presented. Strong evidence of secondary formation of HCOOH is found, with enhancement ratios exceeding 10 times reported emission ratios in fresh plumes. We estimate the total emitted masses for the period July–August 2010 over the center of Western Russia; they are 19–33 Tg (CO), 0.7–2.6 Tg (NH3) and 0.9–3.9 Tg (HCOOH). For NH3 andHCOOH, these quantities are comparable to what is emitted in the course of a whole year by all extratropical forest fires.
Long-term changes of tropospheric NO2 over megacities derived from multiple satellite instruments
Authors: Hilboll A. , Richter A. , Burrows J. P.
Published: December 2012

Abstract. Tropospheric NO2, a key pollutant in particular in cities, has been measured from space since the mid-1990s by the GOME, SCIAMACHY, OMI, and GOME-2 instruments. These data provide a unique global long-term data set of tropospheric pollution. However, the measurements differ in spatial resolution, local time of measurement, and measurement geometry. All these factors can severely impact the retrieved NO2 columns, which is why they need to be taken into account when analysing time series spanning more than one instrument. In this study, we present several ways to explicitly account for the instrumental differences in trend analyses of the NO2 columns derived from satellite measurements, while preserving their high spatial resolution. Both a physical method, based on spatial averaging of the measured earthshine spectra and extraction of a resolution pattern, and statistical methods, including instrument-dependent offsets in the fitted trend function, are developed. These methods are applied to data from GOME and SCIAMACHY separately, to the combined time series and to an extended data set comprising also GOME-2 and OMI measurements. All approaches show consistent trends of tropospheric NO2 for a selection of areas on both regional and city scales, for the first time allowing consistent trend analysis of the full time series at high spatial resolution and significantly reducing the uncertainties of the retrieved trend estimates compared to previous studies. We show that measured tropospheric NO2 columns have been strongly increasing over China, the Middle East, and India, with values over East Central China triplicating from 1996 to 2011. All parts of the developed world, including Western Europe, the United States, and Japan, show significantly decreasing NO2 amounts in the same time period. On a megacity level, individual trends can be as large as +27 ± 3.7% yr−1 and +20 ± 1.9% yr−1 in Dhaka and Baghdad, respectively, while Los Angeles shows a very strong decrease of −6.0 ± 0.37% yr−1. Most megacities in China, India, and the Middle East show increasing NO2 columns of +5–10% yr−1, leading to a doubling to triplication within the observed period. While linear trends derived with the different methods are consistent, comparison of the GOME and SCIAMACHY time series as well as inspection of time series over individual areas shows clear indication of non-linear changes in NO2 columns in response to rapid changes in technology used and the economical situation.
Wintertime peroxyacetyl nitrate (PAN) in the megacity Beijing: the role of photochemical and meteorological processes
Authors: Zhang H. , Xu X. , Lin W. , Wang Y.
Published: December 2012

Abstract. Peroxyacetyl nitrate (PAN) is one of the key photochemical pollutants and acts as an important reservoir for the peroxyacetyl (PA) radical and nitrogen oxides (NOx) over cold and less polluted regions. Previous measurements of PAN in Asian megacities were scarce and mainly conducted for relatively short periods in summer. In this study, we present and analyze the measurements of PAN, O3, NOx, CO, and some meteorological variables, made at an urban site (CMA) in Beijing from 25 January to 22 March 2010. During the observations, the hourly concentration of PAN varied from 0.23 to 3.51 ppb, with an average of 0.70 ppb. Both PAN and O3 showed small but significant diurnal cycle, with PAN peaking around 17:00 LT, three hours later than O3. The observed concentration of PAN is well correlated with that of NOx but not O3. These phenomena indicate that the variations of the winter concentrations of PAN and O3 in urban Beijing are decoupled with each other. Wind conditions and transport of air masses exert very significant impacts on O3, PAN, and other species. The strong WNW-N winds caused elevated concentrations of surface O3 and lower concentrations of PAN, NOx, and CO. Weak winds from the other directions led to enhanced levels of PAN, NOx, and CO and decreased level of O3. Air masses arriving at our site originated either from the boundary layer over the highly polluted N-S-W sector or from the free troposphere over the W-N sector. The descending free-tropospheric air was rich in O3, with an average PAN/O3 ratio smaller than 0.031, while the boundary layer air over the polluted sector contained higher levels of PAN and primary pollutants, with an average PAN/O3 ratio of 0.11. These facts related with meteorological conditions, specifically the air transport conditions, can well explain the observed PAN-O3 decoupling. The impact of meso-scale transport is demonstrated using a case during 21–22 February 2010. In addition to transport, photochemical production is important to PAN in the winter boundary layer over Beijing. The PA concentration is estimated from the measurements of PAN and related variables. The estimated PA concentration for three days with stable atmospheric condition, 7 February, 23 February, and 11 March, are in the range of 0–0.012, 0–0.036, and 0–0.040 ppt, respectively. We found that both the formation reaction and thermal decomposition contributed significantly to PAN's variation. The results here suggest that even in the colder period, both photochemical production and thermal decomposition of PAN in the polluted boundary layer over Beijing are not negligible, with the production exceeding the decomposition.
Intercomparison of shortwave radiative transfer schemes in global aerosol modeling: results from the AeroCom Radiative Transfer Experiment
Authors: Randles C. A. , Kinne S. , Myhre G. , Schulz M. , Stier P. , Fischer J. , Doppler L. , Highwood E. , Ryder C. , Harris B. , Huttunen J. , Ma Y. , Pinker R. T. , Mayer B. , Neubauer D. , Hitzenberger R. , Oreopoulos L. , Lee D. , Pitari G. , Di Genova G. , Quaas J. , Rose Fred G. , Kato S. , Rumbold S. T. , Vardavas I. , Hatzianastassiou N. , Matsoukas C. , Yu H. , Zhang F. , Zhang H. , Lu P.
Published: December 2012

Abstract. In this study we examine the performance of 31 global model radiative transfer schemes in cloud-free conditions with prescribed gaseous absorbers and no aerosols (Rayleigh atmosphere), with prescribed scattering-only aerosols, and with more absorbing aerosols. Results are compared to benchmark results from high-resolution, multi-angular line-by-line radiation models. For purely scattering aerosols, model bias relative to the line-by-line models in the top-of-the atmosphere aerosol radiative forcing ranges from roughly −10 to 20%, with over- and underestimates of radiative cooling at higher and lower sun elevation, respectively. Inter-model diversity (relative standard deviation) increases from ~10 to 15% as sun elevation increases. Inter-model diversity in atmospheric and surface forcing decreases with increased aerosol absorption, indicating that the treatment of multiple-scattering is more variable than aerosol absorption in the models considered. Aerosol radiative forcing results from multi-stream models are generally in better agreement with the line-by-line results than the simpler two-stream schemes. Considering radiative fluxes, model performance is generally the same or slightly better than results from previous radiation scheme intercomparisons. However, the inter-model diversity in aerosol radiative forcing remains large, primarily as a result of the treatment of multiple-scattering. Results indicate that global models that estimate aerosol radiative forcing with two-stream radiation schemes may be subject to persistent biases introduced by these schemes, particularly for regional aerosol forcing.
Mixing state of individual submicron carbon-containing particles and their seasonal variation in urban Guangzhou, China
Authors: Zhang G. , Bi X. , Li L. , Chan L. Y. , Li M. , Wang X. , Sheng G. , Fu J. , Zhou Z.
Published: December 2012

Abstract. Growing evidence suggests that size-resolved mixing state of carbon-containing particles is very critical in determining their optical properties, atmospheric lifetime, and impact on the environment. However, still little is known about the mixing state of particles in urban area of Pearl River Delta (PRD) region, China. To investigate the mixing state of submicron carbon-containing particles, measurements were carried out during spring and fall periods of 2010 using a single particle aerosol mass spectrometer (SPAMS). Approximate 700 000 particles for each period were detected. This is the first report on the size-resolved mixing state of carbon-containing particles by direct observations in PRD region. Cluster analysis of single particle mass spectra was applied to identify carbon-containing particle classes. These classes represented ~80% and ~90% of all the detected particles for spring and fall periods, respectively. Carbon-containing particle classes mainly consisted of biomass/biofuel burning particles (Biomass), organic carbon (OC), fresh elemental carbon (EC-fresh), internally mixed OC and EC (ECOC), internally mixed EC with sulfate (EC-Sulfate), vanadium-containing ECOC (V-ECOC), and amines-containing particles (Amine). In spring, the top three ranked carbon-containing particle classes were ECOC (26.1%), Biomass (23.6%) and OC (10%), respectively. However, the fraction of Biomass particles increased remarkably and predominated (61.0%), while the fraction of ECOC (3.0%) and V-ECOC (0.1%) significantly decreased in fall. To highlight the influence of monsoon on the properties of carbon-containing particles in urban Guangzhou, their size distribution, mixing state, and aerosol acidity were compared between spring and fall seasons. In addition, a case study was also performed to investigate how the formation of fog and haze influenced the mixing state of carbon-containing particles. These results are of importance in understanding atmospheric chemistry and modeling direct and indirect forcing of carbon-containing particles.
Antarctic new particle formation from continental biogenic precursors
Authors: Kyrö E.-M. , Kerminen V.-M. , Virkkula A. , Dal Maso M. , Parshintsev J. , Ruíz-Jimenez J. , Forsström L. , Manninen H. E. , Riekkola M.-L. , Heinonen P. , Kulmala M.
Published: December 2012

Abstract. Over Antarctica, aerosol particles originate almost entirely from marine areas, with minor contribution from long-range transported dust or anthropogenic material. The Antarctic continent itself, unlike all other continental areas, has been thought to be practically free of aerosol sources. Here we present evidence of local aerosol production associated with melt-water ponds in the continental Antarctica. We show that in air masses passing such ponds, new aerosol particles are efficiently formed and these particles grow up to sizes where they may act as cloud condensation nuclei (CCN). The precursor vapours responsible for aerosol formation and growth originate very likely from highly abundant cyanobacteria Nostoc commune (Vaucher) communities of local ponds. This is the first time when freshwater vegetation has been identified as an aerosol precursor source. The influence of the new source on clouds and climate may increase in future Antarctica, and possibly elsewhere undergoing accelerating summer melting of semi-permanent snow cover.
Evidence and quantitation of aromatic organosulfates in ambient aerosols in Lahore, Pakistan
Authors: Kundu S. , Quraishi T. A. , Yu G. , Suarez C. , Keutsch F. N. , Stone E. A.
Published: December 2012

Abstract. Organosulfates are important components of atmospheric organic aerosols, yet their structures, abundances, sources and formation processes are not adequately understood. This study presents the identification and quantitation of benzyl sulfate in atmospheric aerosols, which is the first reported atmospheric organosulfate with aromatic carbon backbone. Benzyl sulfate was identified and quantified in fine particulate matter (PM2.5) collected in Lahore, Pakistan during 2007–2008. An authentic standard of benzyl sulfate was synthesized, standardized, and identified in atmospheric aerosols using ultra-performance liquid chromatography (UPLC) coupled with quadrupole time-of-flight (Q-ToF) mass spectrometry (MS). Benzyl sulfate was quantified in aerosol samples using UPLC coupled to negative electrospray ionization triple quadrupole (TQ) MS. The highest benzyl sulfate concentrations were recorded in November and January 2007 (0.50 ± 0.11 ng m−3) whereas the lowest concentration was observed in July (0.05 ± 0.02 ng m−3). To evaluate matrix effects, benzyl sulfate concentrations were determined using external calibration and the method of standard addition; comparable concentrations were detected by the two methods, which ruled out significant matrix effects in benzyl sulfate quantitation. Three additional organosulfates with m/z 187, 201 and 215 were qualitatively identified as aromatic organosulfates with additional methyl substituents by high-resolution mass measurements and tandem MS. The observed aromatic organosulfates form a homologous series analogous to toluene, xylene, and trimethylbenzene, which are abundant anthropogenic volatile organic compounds (VOC), suggesting that aromatic organosulfates may be formed by secondary reactions. Further studies are needed to elucidate the sources and formation pathways of aromatic organosulfates in the atmosphere.
Quantitative evaluation of emission control of primary and secondary organic aerosol sources during Beijing 2008 Olympics
Authors: Guo S. , Hu M. , Guo Q. , Zhang X. , Schauer J. J. , Zhang R.
Published: December 2012

Abstract. To explore the primary and secondary sources of fine organic particles after the aggressive implementation of air pollution controls during 2008 Beijing Olympic Games, 12-h PM2.5 concentrations were measured at one urban and one upwind rural site during the CAREBeijing-2008 (Campaigns of Air quality REsearch in Beijing and surrounding region) summer field campaign. The PM2.5 concentrations were 72.5±43.6μg m3 and 64.3±36.2μg m−3 at the urban site and rural site, respectively, which were the lowest in recent years due to the implementation of drastic control measures and favorable weather conditions. Five primary and four secondary fine organic particle sources were quantified using a CMB (chemical mass balance) model and tracer-yield method. Compared with previous studies in Beijing, the contribution of vehicle emission increased, with diesel engines contributing 16.2±5.9% and 14.5±4.1% to the total organic carbon (OC) concentrations and gasoline vehicles accounting for 10.3±8.7% and 7.9±6.2% of the OC concentrations at two sites. Due to the implementation of emission control measures, the OC concentrations from important primary sources have been reduced, and secondary formation has become an important contributor to fine organic aerosols. Compared with the non-controlled period, primary vehicle contributions were reduced by 30% and 24% in the urban and regional area, and reductions in the contribution from coal combustion were 57% and 7%, respectively. These results demonstrate the emission control measures significantly alleviated the primary organic particle pollution in and around Beijing. However, the control effectiveness of secondary organic particles was not significant.
Characterization of light-absorbing carbon particles at three altitudes in East Asian outflow by transmission electron microscopy
Authors: Zhu J. , Crozier P. A. , Anderson J. R.
Published: December 2012

Abstract. The morphology, microstructure, and composition of the submicron fraction of individual light-absorbing carbon (LAC) particles collected by research aircraft during the ACE-Asia project above the Yellow Sea at altitudes of 120, 450 and 1500 m are investigated by transmission electron microscopy (TEM), and energy dispersive X-ray spectroscopy (EDS). Two types of carbonaceous particles, small spherule soot with graphitic spherules and amorphous carbonaceous spheres (brown carbon), are found at all altitudes in high concentration. For soot particles, emphasis of the study is on the component subparticles (spherules). The nanoscopic structures of the small spherule soot show no significant difference at three altitudes although the size distribution of primary spherules showed that 70% of the total volume lies in the ranges 30–50, 50–85 and 30–50 nm, respectively. For the amorphous carbonaceous spheres, 70% of the total volume from three altitudes lies in the range 200–350, 160–470 and 150–320 nm, respectively. Within the size fraction studied (submicron, with most particles in the range 50 to 500 nm) the number concentration ratios of the amorphous carbonaceous spheres to primary spherules in soot at altitudes of 120, 450 and 1500 m are about 1, 1.5 and 10, respectively and their volume ratios are about 260, 50 and 1400. Lower relative concentrations of large spherule soot with intermediate graphitic structure were observed at 120 m. Also, low relative number concentrations of carbon cenosphere were observed at 120 and 1500 m. A key result of the study is that in vertically stratified outflow from East Asia, the character of LAC may have strong variance with altitude thus resulting in optical characteristics that vary with altitude. Also, apparent "aging" of LAC deduced from samples at multiple ground stations may instead reflect differences in the original carbon aerosols.
Limitations of wind extraction from 4-D-Var assimilation of trace gases
Authors: Allen D. R. , Hoppel K. W. , Nedoluha G. E. , Kuhl D. D. , Baker N. L. , Xu L. , Rosmond T. E.
Published: December 2012

Abstract. Time-dependent variational data assimilation allows the possibility of extracting wind information from observations of long-lived trace gases. Since trace gas observations are not available at sufficient resolution for deriving feature-track winds, they must be combined with model background information to produce an analysis. If done with time-dependent variational assimilation, wind information may be extracted via the adjoint of the linearized tracer continuity equation. This paper presents idealized experiments that illustrate the mechanics of tracer-wind extraction and demonstrate some of the limitations of this procedure. We first examine tracer-wind extraction using a simple one-dimensional advection equation. The analytic solution for a single trace gas observation is discussed along with numerical solutions for multiple observations. The limitations of tracer-wind extraction are then explored using highly idealized ozone experiments performed with a development version of the Navy Global Environmental Model (NAVGEM) in which stratospheric globally-distributed hourly stratospheric ozone profiles are assimilated in a single 6-h update cycle in January 2009. Starting with perfect background ozone conditions, but imperfect dynamical conditions, ozone errors develop over the 6-h background window. Wind increments are introduced in the analysis in order to reduce the differences between background ozone and ozone observations. For "perfect" observations (unbiased and no random error), this results in root mean square (RMS) vector wind error reductions of up to ∼ 3 m s−1 in the winter hemisphere and tropics. Wind extraction is more difficult in the summer hemisphere due to weak ozone gradients and smaller background wind errors. The limitations of wind extraction are also explored for observations with imposed random errors and for limited sampling patterns. As expected, the amount of wind information extracted degrades as observation errors or data voids increase. In the case of poorly specified observation error covariances, assimilation of ozone data with imposed errors may result in erroneous wind increments, since the assimilation is constrained too tightly to the noisy observations.
Mass deposition fluxes of Saharan mineral dust to the tropical northeast Atlantic Ocean: an intercomparison of methods
Authors: Niedermeier N. , Held A. , Müller T. , Heinold B. , Schepanski K. , Tegen I. , Kandler K. , Ebert M. , Weinbruch S. , Read K. , Lee J. , Fomba K. W. , Müller K. , Herrmann H. , Wiedensohler A.
Published: December 2012

Abstract. The aim of this study is to determine the mass deposition flux of mineral dust to the tropical northeast Atlantic Ocean at the Cape Verde Atmospheric Observatory (CVAO) on the island Sao Vicente for January 2009. Five different methods were applied to estimate the deposition flux, using different meteorological and microphysical measurements, remote sensing, and regional dust transport simulations. The set of observations comprises micrometeorological measurements with an ultra-sonic anemometer and profile measurements using 2-D anemometers at two different heights, and microphysical measurements of the size-resolved mass concentrations of mineral dust. In addition, the total mass concentration of mineral dust was derived from absorption photometer observations and passive sampling. The regional dust model COSMO-MUSCAT was used for simulations of dust emission and transport, including dry and wet deposition processes. The four observation-based methods yield a monthly average deposition flux of mineral dust of 12–29 ng m−2 s−1. The simulation results come close to the upper range of the measurements with an average value of 47 ng m−2 s−1. It is shown, that the mass deposition flux of mineral dust obtained by the combination of micrometeorological (ultra-sonic anemometer) and microphysical measurements (particle mass size distribution of mineral dust) is within 5% to modeled mass deposition fluxes when the mineral dust is relatively homogenously distributed over the investigated area.
Simultaneous observations of large-scale traveling ionospheric disturbances on the nightside and dayside middle latitude
Authors: Cai H. T. , Yin F. , Ma S. Y. , Xu J. S. , Liu Y. W.
Published: December 2012

Abstract. In this paper, we present further observational evidence for the transpolar propagation of large-scale traveling ionospheric disturbances (LSTIDs) from their nightside source region to the dayside reported by Cai et al. (2011). Slant total electron content (STEC) observed by longitudinally aligned GPS receiver chains in North American and European sectors was analyzed to demonstrate presences of LSTIDs at both nightside and dayside mid-latitude. Signatures of TID were inferred from phase difference in time series of STEC perturbations (TECP) derived from measurements of ground-based GPS receivers, which are separated by hundreds of kilometers longitudinally. Periods of the daytime and nighttime ionospheric disturbances were estimated to be around 128 min, being in good agreement with that of the transpolar AGW (atmospheric gravity wave) recorded by EISCAT (European Incoherent Scatter Scientific Association)/ESR (EISCAT Svalbard Radar) radars. On the dayside, the LSTID moved equatorward with an average phase speed of ~440 m s−1. In North American sector, however, southward speed of the nighttime LSTID was much slower, being around 160 m s−1. We suggest that the observed daytime and nighttime mid-latitude LSTIDs are likely to have the same source region, being located somewhere at nighttime auroral latitude. Having been launched on the nightside, the waves propagate simultaneously equatorward and poleward. The equatorward-moving waves are recorded by GPS receiver chain in North American sector. The poleward-moving waves, however, cross the polar cap from nightside to dayside and then are detected consecutively at high and mid-latitudes by EISCAT/ESR radars and GPS receiver chains, respectively.
Coral Patch seamount (NE Atlantic) – a sedimentological and macrofaunal reconnaissance based on video and hydroacoustic surveys
Authors: Wienberg C. , Wintersteller P. , Beuck L. , Hebbeln D.
Published: December 2012

Abstract. The present study provides new knowledge about the so far largely unexplored Coral Patch seamount which is located in the NE Atlantic Ocean half-way between the Iberian Peninsula and Madeira. For the first time a detailed hydroacoustic mapping (MBES) in conjunction with video surveys (ROV, camera sled) were performed to describe the sedimentological and biological characteristics of this sub-elliptical ENE-WSW elongated seamount. Video observations were restricted to the south-western summit area of Coral Patch seamount (area: ~ 8 km2, water depth: 560–760 m) and revealed that this part of the summit is dominated by exposed hard substrate, whereas soft sediment is just a minor substrate component. Although exposed hardgrounds are dominant for this summit area, and thus, offer suitable habitat for settlement by benthic organisms, the macrofauna shows rather low abundance and diversity. In particular, scleractinian framework-building cold-water corals are apparently rare with very few isolated and small-sized live occurrences of the species Lophelia pertusa and Madrepora oculata. In contrast, dead coral framework and coral rubble are more frequent pointing to a higher abundance of cold-water corals on Coral Patch during the recent past. This is even supported by the observation of fishing lines that got entangled with rather fresh-looking coral frameworks. Overall, long lines and various species of commercially important fish were frequently observed emphasising the potential of Coral Patch as an important target for fisheries that may have impacted the entire benthic community. Hydroacoustic seabed classification covered the entire summit of Coral Patch and its northern and southern flanks (area: 560 km2; water depth: 560–2660 m) and revealed extended areas dominated by mixed and soft sediments at the northern flank and to a minor degree at its easternmost summit and southern flank. Nevertheless, also these data predict most of the summit area to be dominated by exposed bedrock which would offer suitable habitat for benthic organisms. By comparing the locally restricted video observations and the broad-scale monitoring of a much larger and deeper seafloor area as derived by hydroacoustic seabed classification, it becomes obvious that habitat information obtained by in situ sampling may provide a rather scattered pattern about the entire seamount ecosystem. Solely with a combination of both methods, a satisfactory approach to describe the diverse characteristics of a seamount ecosystem can be derived which is in turn indispensable for future scientific monitoring campaigns as well as management and conservation purposes.
Modeling soil bulk density at the landscape scale and its contributions to C stock uncertainty
Authors: Taalab K. P. , Corstanje R. , Creamer R. , Whelan M. J.
Published: December 2012

Abstract. Soil bulk density (Db) is a major contributor to uncertainties in landscape-scale carbon and nutrient stock estimation. However, it is time consuming to measure and is, therefore, frequently predicted using surrogate variables, such as soil texture. Using this approach is of limited value for estimating landscape scale inventories, as its accuracy beyond the sampling point at which texture is measured becomes highly uncertain. In this paper, we explore the ability of soil landscape models to predict soil Db using a suite of landscape attributes and derivatives for both topsoil and subsoil. The models were constructed using random forests and artificial neural networks. Using these statistical methods, we have produced a spatially distributed prediction of Db on a 100m × 100m grid which was shown to significantly improve topsoil carbon stock estimation. In comparison to using mean values from point measurements, the error associated with predictions was over three times lower using the gridded prediction. Within our study area of the Midlands, UK, we found that the gridded prediction of Db produced a stock inventory of nearly 8 million tonnes of carbon less than the mean method. Furthermore, the gridded approach was particularly useful in improving organic carbon (OC) stock estimation for fine-scale landscape units at which many landscape-atmosphere interaction models operate.
Impacts of trait variation through observed trait-climate relationships on performance of a representative Earth System model: a conceptual analysis
Authors: Verheijen L. M. , Brovkin V. , Aerts R. , Bönisch G. , Cornelissen J. H. C. , Kattge J. , Reich P. B. , Wright I. J. , van Bodegom P. M.
Published: December 2012

Abstract. In current dynamic global vegetation models (DGVMs), including those incorporated into Earth System Models (ESMs), terrestrial vegetation is represented by a small number of plant functional types (PFTs), each with fixed properties irrespective of their predicted occurrence. This contrasts with natural vegetation, in which many plant traits vary systematically along geographic and environmental gradients. In the JSBACH DGVM, which is part of the MPI-ESM, we allowed three traits (specific leaf area (SLA), maximum carboxylation rate at 25 °C (Vcmax25) and maximum electron transport rate (Jmax25)) to vary within PFTs via trait-climate relationships based on a large trait database. For all three traits, the means of observed natural trait values strongly deviated from values used in the default model, with mean differences of 32.3% for Vcmax25, 26.8% for Jmax25 and 17.3% for SLA. Compared to the default simulation, allowing trait variation within PFTs resulted in GPP differences up to 50% in the tropics, in > 35% different dominant vegetation cover, and a closer match with a natural vegetation map. The discrepancy between default trait values and natural trait variation, combined with the substantial changes in simulated vegetation properties, together emphasize that incorporating observational data based on the ecological concepts of environmental filtering will improve the modeling of vegetation behavior in DGVMs and as such will enable more reliable projections in unknown climates.