bluuebunny/crossref_metadata_2025 huggingface dataset:
Perceived Self-Efficacy of Preservice Agriculture Teachers toward Specific SAE Competencies
Authors: Rubenstein Eric D. , Thoron Andrew C. , Estepp Christopher M.
Published: January 2016

Since its inception, school-based agricultural education in the United States has utilized the home project method, later known as a supervised agricultural experience program (SAE), as a way to provide students with contextual, hands-on learning experiences outside of class that complement classroom learning. While most teachers realize the benefits of SAE programs, the use of SAE has declined over time, and many agriculture teachers new to the profession may not be as proficient in implementing SAE programs. Therefore, the purpose of this study was to determine preservice agriculture teachers’ self-efficacy of the AAAE-SAE Competencies. Results indicated that 95% of the respondents considered SAE to be important or somewhat important components of agricultural education. Additionally, all respondents reported to have moderately high efficaciousness for their ability to perform all of the SAE competencies. What is more, few differences were found between preservice teachers who possessed SAE and agricultural education experience versus preservice teachers who had little or no experience with SAE and agricultural education. The researchers recommend that teacher preparation program in agriculture continue to provide instruction over SAE and should implement learning experiences in SAE that provide authentic, relevant instruction to preservice teachers on developing, implementing, maintaining, sustaining, evaluating, and supervising an SAE program.
Perceived Work-Life Balance Ability, Job Satisfaction, and Professional Commitment among Agriculture Teachers
Authors: Sorensen Tyson J. , McKim Aaron J.
Published: January 2016

Agriculture teachers participate in various work and life roles, which can create challenges when trying to balance the pressures and responsibilities associated with each role. When one is unable to balance and prioritize between roles, both satisfaction and professional commitment may be reduced. The purpose of this study was to describe Oregon agriculture teachers’ job satisfaction, professional commitment, and perceived ability to balance work and life roles. Additionally, this study sought to describe the relationship between perceived ability to balance work and life roles, job satisfaction, and professional commitment. Sex, marital status, parental status, and career stage had only small to negligible effects on job satisfaction, professional commitment, and work-life balance. Statistically significant positive correlations were found between job satisfaction, professional commitment, and work-life balance. Implications and recommendations are discussed.
How Cognitive Style and Problem Complexity Affect Preservice Agricultural Education Teachers’ Abilities to Solve Problems in Agricultural Mechanics
Authors: Blackburn J. Joey , Robinson J. Shane , Lamm Alexa J.
Published: January 2016

The purpose of this experimental study was to determine the effects of cognitive style and problem complexity on Oklahoma State University preservice agriculture teachers’ (N = 56) ability to solve problems in small gasoline engines. Time to solution was operationalized as problem solving ability. Kirton’s Adaption-Innovation Inventory was administered to determine cognitive style as more adaptive or more innovative. Preservice teachers were assigned randomly, by cognitive style, to solve either a simple or complex problem in a small gasoline engine. The simple problem was related to the electrical system of the engine – specifically, a closed spark plug gap. The complex problem was related to the fuel/air delivery system; specifically, debris was placed into the main jet of the carburetor. To determine content knowledge, students were administered a 30-item, researcher developed criterion-referenced test. The findings of this study indicated that no statistically significant differences existed in content knowledge based on cognitive style. All students were able to solve their problem successfully; however, regarding time to solution, a statistically significant interaction effect existed between cognitive style and problem complexity. A simple main effects test revealed a statistically significant difference between the more innovative students based on problem complexity.
The expression of the SCD1 gene and its correlation with fattening and carcass traits in sheep
Authors: Ropka-Molik K. , Knapik J. , Pieszka M. , Szmatoła T.
Published: January 2016

Abstract. Stearoyl-CoA desaturase 1 (SCD1) is a critical enzyme that catalyzes the synthesis of monounsaturated fatty acids and is involved in several signaling pathways related to lipid metabolism. The objective of the present study was to estimate the expression of the SCD1 gene in three different ovine tissues strongly associated with lipid homeostasis. The SCD1 gene expression measurement was performed on three tissues (liver, subcutaneous fat, perirenal fat) originated from 15 old-type Polish Merino sheep. The SCD1 transcript abundance was evaluated based on the two most stable endogenous controls (RPS2 – ribosomal protein S2; ATP5G2 – H(+)-transporting ATP synthase). The highest expression of the SCD1 gene was observed in ovine subcutaneous fat compared to perirenal fat and liver. Furthermore, the present research indicated the significant correlation between ovine SCD1 transcript abundance and several important production traits. The expression of the SCD1 gene in liver and perirenal fat highly positively correlated with the feed : gain ratio, test of daily gain and age of the animals at slaughter. Moreover, in both tissues, the SCD1mRNA level positively correlated with weight and content of perirenal fat and subcutaneous fat (R =  0.64, 0.8, 0.6, respectively) and negatively with assessment of external fat content with the use of the EUROP scale (R = −0.64). The SCD1 expression in subcutaneous fat also corresponds with back fat of blade chop and thickness of longissimus dorsi muscles evaluated using USG (ultrasonography) (R =  −0.6 and 0.62, respectively). The significant correlation between SCD1 transcript abundance and fattening and slaughtering traits indicate the ability to improve important production traits in sheep via modification of expression of the SCD1 gene.
The effect of sex, carcass mass, back fat thickness and lean meat content on pork ham and loin characteristics
Authors: Knecht D. , Duziński K.
Published: January 2016

Abstract. This study was designed to determine the ratio of ham and loin in half-carcasses and the tissue composition of these cuts. The research material consisted of 140 pig carcasses. The experimental materials were derived from the Polish commercial population of fattener pigs. Genetic material representing the most commonly slaughtered fatteners in Poland. Fatteners for the study came from several suppliers. All fatteners were kept in similar farms complying with principles of animal welfare. The right half-carcasses were divided into different groups, regardless of sex, half-carcass mass, back fat thickness and lean meat content class. Ham and loin obtained from carcasses were subjected to a detailed dissection, and the percentage of ham and loin in the carcass and the overall percentage of of the cuts in relation to the entire half-carcass were calculated. Gilts were characterized by a higher content of ham in half-carcasses than barrows (P  ≤ 0.01). The increase in back fat thickness reduced the content of ham in half-carcasses and increased the content of loin (P ≤ 0.01). A similar trend was shown for the lean meat content class parameter. Additionally, interaction (P  ≤ 0.01) between back fat thickness and meat content with respect to the percentage content of loin in carcasses was noted. Gilts were characterised by about a 1.38 % higher proportion of muscles in the ham (P  ≤ 0.05) and a 0.47 % lower proportion of intermuscular fat (P  ≤ 0.01). An average increase of five point in back fat thickness increases the amount of subcutaneous fat with skin (P  ≤ 0.01) and intermuscular fat (P  ≤ 0.01) and reduces muscle (P  ≤ 0.01) and bone (P  ≤ 0.05 and P  ≤ 0.01) levels. The interaction of percentage content of muscles in ham was observed (P = 0.04). The meat content class of carcasses did not only affect the level of bones in ham. It was confirmed that sex affected all the analysed dissection elements of the loin. Back fat thickness and meat content classes were present in almost identical amounts in loin tissues (P  ≤ 0.05 and P  ≤ 0.01). Half-carcass mass showed a strong negative correlation with bone content in ham and loin (r = −0.35 and r = −0.21, respectively). Back fat thickness and meat content strongly and inversely correlated with the content of ham and loin in half-carcasses (r = −0.41 and r = 0.59 for back fat thickness; r = 0.66 and r = −0.57 for lean meat content). Close and inverse correlations of back fat thickness and lean meat content were observed with regard to their content in ham and loin (P  ≤ 0.01).
The peripartum period influenced the serum macromineral profile in mares
Authors: Bazzano M. , Giudice E. , Giannetto C. , Fazio F. , Scollo C. , Piccione G.
Published: January 2016

Abstract. Changes in metabolic requirements during pregnancy may produce nutritional imbalances predisposing mares to pathological conditions. Therefore, we aimed to examine changes in serum macrominerals during the peripartum period in mares. Fifteen pregnant mares (Group A) were monitored starting at the 263rd day of pregnancy until the 21st day after foaling. Seven non-pregnant and non-lactating mares were used as a control group (Group B). Group A was subjected to blood sampling within 24 ± 12 h after parturition (P) and then 7, 14 and 21 days after foaling (+1, +2, +3 weeks, respectively). Group B was subjected to regular sampling throughout the study to ensure that seasonal changes had no significant effect on studied parameters. Serum samples were analysed for serum electrolytes including sodium (Na+), potassium (K+), calcium (Ca+ + ), phosphorus (P+), chloride (Cl−) and magnesium (Mg+ + ). Two-way repeated measures of analysis of variance (ANOVA) was applied to evaluate significant effects of peripartum on electrolyte concentrations. Group A showed a decrease in Cl− concentrations (P = 0.011) after foaling and lower P+ concentrations (P = 0.015) compared to Group B throughout the study. The linear regression model showed an increase in Na+ concentrations (P = 0.002) and a gradual decrease in serum Ca+ +  (P = 0.001) during pregnancy. Because the most significant changes in serum electrolytes occurred within 2 weeks before and 2 weeks after foaling, monitoring serum electrolyte concentrations would indicate whether the mare needs further mineral supplementation at this stage. The significant changes in a mare's macromineral profile that we observed over the peripartum provide enhanced knowledge about mineral interrelations and their modifications during specific physiological conditions such as late pregnancy and early postpartum.
Conceptual design of a measurement network of the global change
Authors: Hari P. , Petäjä T. , Bäck J. , Kerminen V.-M. , Lappalainen H. K. , Vihma T. , Laurila T. , Viisanen Y. , Vesala T. , Kulmala M.
Published: January 2016

Abstract. The global environment is changing rapidly due to anthropogenic emissions and actions. Such activities modify aerosol and greenhouse gas concentrations in the atmosphere, leading to regional and global climate change and affecting, e.g., food and fresh-water security, sustainable use of natural resources and even demography. Here we present a conceptual design of a global, hierarchical observation network that can provide tools and increased understanding to tackle the inter-connected environmental and societal challenges that we will face in the coming decades. The philosophy behind the conceptual design relies on physical conservation laws of mass, energy and momentum, as well as on concentration gradients that act as driving forces for the atmosphere-biosphere exchange. The network is composed of standard, flux and/or advanced and flagship stations, each of which having specific and identified tasks. Each ecosystem type on the globe has its own characteristic features that have to be taken into consideration. The hierarchical network as a whole is able to tackle problems related to large spatial scales, heterogeneity of ecosystems and their complexity. The most comprehensive observations are envisioned to occur in flagship stations, with which the process-level understanding can be expanded to continental and global scales together with advanced data analysis, Earth system modelling and satellite remote sensing. The denser network of the flux and standard stations allows application and up-scaling of the results obtained from flagship stations to the global level.
Historic records of organic compounds from a high Alpine glacier: influences of biomass burning, anthropogenic emissions, and dust transport
Authors: Müller-Tautges C. , Eichler A. , Schwikowski M. , Pezzatti G. B. , Conedera M. , Hoffmann T.
Published: January 2016

Abstract. Historic records of α-dicarbonyls (glyoxal, methylglyoxal), carboxylic acids (C6–C12 dicarboxylic acids, pinic acid, p-hydroxybenzoic acid, phthalic acid, 4-methylphthalic acid), and ions (oxalate, formate, calcium) were determined with annual resolution in an ice core from Grenzgletscher in the southern Swiss Alps, covering the time period from 1942 to 1993. Chemical analysis of the organic compounds was conducted using ultra-high-performance liquid chromatography (UHPLC) coupled to electrospray ionization high-resolution mass spectrometry (ESI-HRMS) for dicarbonyls and long-chain carboxylic acids and ion chromatography for short-chain carboxylates. Long-term records of the carboxylic acids and dicarbonyls, as well as their source apportionment, are reported for western Europe. This is the first study comprising long-term trends of dicarbonyls and long-chain dicarboxylic acids (C6–C12) in Alpine precipitation. Source assignment of the organic species present in the ice core was performed using principal component analysis. Our results suggest biomass burning, anthropogenic emissions, and transport of mineral dust to be the main parameters influencing the concentration of organic compounds. Ice core records of several highly correlated compounds (e.g., p-hydroxybenzoic acid, pinic acid, pimelic, and suberic acids) can be related to the forest fire history in southern Switzerland. P-hydroxybenzoic acid was found to be the best organic fire tracer in the study area, revealing the highest correlation with the burned area from fires. Historical records of methylglyoxal, phthalic acid, and dicarboxylic acids adipic acid, sebacic acid, and dodecanedioic acid are comparable with that of anthropogenic emissions of volatile organic compounds (VOCs). The small organic acids, oxalic acid and formic acid, are both highly correlated with calcium, suggesting their records to be affected by changing mineral dust transport to the drilling site.
The diurnal cycle of rainfall over New Guinea in convection-permitting WRF simulations
Authors: Hassim M. E. E. , Lane T. P. , Grabowski W. W.
Published: January 2016

Abstract. In this study, we examine the diurnal cycle of rainfall over New Guinea using a series of convection-permitting numerical simulations with the Weather Research and Forecasting (WRF) model. We focus our simulations on a period of suppressed regional-scale conditions (February 2010) during which local diurnal forcings are maximised. Additionally, we focus our study on the occurrence and dynamics of offshore-propagating convective systems that contribute to the observed early-morning rainfall maximum north-east of New Guinea.In general, modelled diurnal precipitation shows good agreement with satellite-observed rainfall, albeit with some timing and intensity differences. The simulations also reproduce the occurrence and variability of overnight convection that propagate offshore as organised squall lines north-east of New Guinea. The occurrence of these offshore systems is largely controlled by background conditions. Days with offshore-propagating convection have more middle tropospheric moisture, larger convective available potential energy, and greater low-level moisture convergence. Convection has similar characteristics over the terrain on days with and without offshore propagation.The offshore-propagating convection manifests via a multi-stage evolutionary process. First, scattered convection over land, which is remnant of the daytime maximum, moves towards the coast and becomes reorganised near the region of coastal convergence associated with the land breeze. The convection then moves offshore in the form of a squall line at  ∼ 5 ms−1. In addition, cool anomalies associated with gravity waves generated by precipitating land convection propagate offshore at a dry hydrostatic gravity wave speed (of  ∼ 15 ms−1) and act to destabilise the coastal/offshore environment prior to the arrival of the squall line. Although the gravity wave does not appear to initiate the convection or control its propagation, it should contribute to its longevity and maintenance. The results highlight the importance of terrain and coastal effects along with gravity waves in contributing to the diurnal cycle over the Maritime Continent, especially the offshore precipitation maxima adjacent to quasi-linear coastlines.
Effects of emission reductions on organic aerosol in the southeastern United States
Authors: Blanchard C. L. , Hidy G. M. , Shaw S. , Baumann K. , Edgerton E. S.
Published: January 2016

Abstract. Long-term (1999 to 2013) data from the Southeastern Aerosol Research and Characterization (SEARCH) network are used to show that anthropogenic emission reductions led to important decreases in fine-particle organic aerosol (OA) concentrations in the southeastern US On average, 45 % (range 25 to 63 %) of the 1999 to 2013 mean organic carbon (OC) concentrations are attributed to combustion processes, including fossil fuel use and biomass burning, through associations of measured OC with combustion products such as elemental carbon (EC), carbon monoxide (CO), and nitrogen oxides (NOx). The 2013 mean combustion-derived OC concentrations were 0.5 to 1.4 µg m−3 at the five sites operating in that year. Mean annual combustion-derived OC concentrations declined from 3.8 ± 0.2 µg m−3 (68 % of total OC) to 1.4 ± 0.1 µg m−3 (60 % of total OC) between 1999 and 2013 at the urban Atlanta, Georgia, site (JST) and from 2.9 ± 0.4 µg m−3 (39 % of total OC) to 0.7 ± 0.1 µg m−3 (30 % of total OC) between 2001 and 2013 at the urban Birmingham, Alabama (BHM), site. The urban OC declines coincide with reductions of motor vehicle emissions between 2006 and 2010, which may have decreased mean OC concentrations at the urban SEARCH sites by > 2 µg m−3. BHM additionally exhibits a decline in OC associated with SO2 from 0.4 ± 0.04 µg m−3 in 2001 to 0.2 ± 0.03 µg m−3 in 2013, interpreted as the result of reduced emissions from industrial sources within the city. Analyses using non-soil potassium as a biomass burning tracer indicate that biomass burning OC occurs throughout the year at all sites. All eight SEARCH sites show an association of OC with sulfate (SO4) ranging from 0.3 to 1.0 µg m−3 on average, representing  ∼  25 % of the 1999 to 2013 mean OC concentrations. Because the mass of OC identified with SO4 averages 20 to 30 % of the SO4 concentrations, the mean SO4-associated OC declined by  ∼  0.5 to 1 µg m−3 as SO4 concentrations decreased throughout the SEARCH region. The 2013 mean SO4 concentrations of 1.7 to 2.0 µg m−3 imply that future decreases in mean SO4-associated OC concentrations would not exceed  ∼  0.3 to 0.5 µg m−3. Seasonal OC concentrations, largely identified with ozone (O3), vary from 0.3 to 1.4 µg m−3 ( ∼  20 % of the total OC concentrations).
Effect of gravity wave temperature fluctuations on homogeneous ice nucleation in the tropical tropopause layer
Authors: Dinh T. , Podglajen A. , Hertzog A. , Legras B. , Plougonven R.
Published: January 2016

Abstract. The impact of high-frequency fluctuations of temperature on homogeneous nucleation of ice crystals in the vicinity of the tropical tropopause is investigated using a bin microphysics scheme for air parcels. The imposed temperature fluctuations come from measurements during isopycnic balloon flights near the tropical tropopause. The balloons collected data at high frequency, guaranteeing that gravity wave signals are well resolved.With the observed temperature time series, the numerical simulations with homogeneous freezing show a full range of ice number concentration (INC) as previously observed in the tropical upper troposphere. In particular, a low INC may be obtained if the gravity wave perturbations produce a non-persistent cooling rate (even with large magnitude) such that the absolute change in temperature remains small during nucleation. This result is explained analytically by a dependence of the INC on the absolute drop in temperature (and not on the cooling rate). This work suggests that homogeneous ice nucleation is not necessarily inconsistent with observations of low INCs.
Global tropospheric ozone variations from 2003 to 2011 as seen by SCIAMACHY
Authors: Ebojie F. , Burrows J. P. , Gebhardt C. , Ladstätter-Weißenmayer A. , von Savigny C. , Rozanov A. , Weber M. , Bovensmann H.
Published: January 2016

Abstract. An analysis of the tropospheric ozone (O3) columns (TOCs) derived from SCIAMACHY limb-nadir-matching (LNM) observations during the period 2003–2011, focusing on global variations in TOC, is described. The changes are derived using a multivariate linear regression model. TOC shows changes of −0.2 ± 0.4, 0.3 ± 0.4, 0.1 ± 0.5 and 0.1 ± 0.2 % yr−1, which are not statistically significant at the 2σ level in the latitude bands 30–50° N, 20° S–0, 0–20° N and 50–30° S, respectively. Tropospheric O3 shows statistically significant increases over some regions of South Asia (1–3 % yr−1), the South American continent (up to 2 % yr−1), Alaska (up to 2 % yr−1) and around Congo in Africa (up to 2 % yr−1). Significant increase in TOC is determined off the continents including Australia (up to 2 % yr−1), Eurasia (1–3 % yr−1) and South America (up to 3 % yr−1). Significant decrease in TOC (up to −3 % yr−1) is observed over some regions of the continents of North America, Europe and South America. Over the oceanic regions including the Pacific, North Atlantic and Indian oceans, significant decreases in TOC (−1 to −3 % yr−1) were observed. In addition, the response of the El Niño–Southern Oscillation (ENSO) and quasi-biennial oscillation (QBO) to changes in TOC for the period 2003–2011 was investigated. The result shows extensive regions, mostly in the tropics and Northern Hemisphere extratropics, of significant ENSO responses to changes in TOC and a significant QBO response to TOC changes over some regions.
How large-scale subsidence affects stratocumulus transitions
Authors: van der Dussen J. J. , de Roode S. R. , Siebesma A. P.
Published: January 2016

Abstract. Some climate modeling results suggest that the Hadley circulation might weaken in a future climate, causing a subsequent reduction in the large-scale subsidence velocity in the subtropics. In this study we analyze the cloud liquid water path (LWP) budget from large-eddy simulation (LES) results of three idealized stratocumulus transition cases, each with a different subsidence rate. As shown in previous studies a reduced subsidence is found to lead to a deeper stratocumulus-topped boundary layer, an enhanced cloud-top entrainment rate and a delay in the transition of stratocumulus clouds into shallow cumulus clouds during its equatorwards advection by the prevailing trade winds. The effect of a reduction of the subsidence rate can be summarized as follows. The initial deepening of the stratocumulus layer is partly counteracted by an enhanced absorption of solar radiation. After some hours the deepening of the boundary layer is accelerated by an enhancement of the entrainment rate. Because this is accompanied by a change in the cloud-base turbulent fluxes of moisture and heat, the net change in the LWP due to changes in the turbulent flux profiles is negligibly small.
The impact of shipping emissions on air pollution in the greater North Sea region – Part 1: Current emissions and concentrations
Authors: Aulinger A. , Matthias V. , Zeretzke M. , Bieser J. , Quante M. , Backes A.
Published: January 2016

Abstract. The North Sea is one of the areas with the highest ship traffic densities worldwide. At any time, about 3000 ships are sailing its waterways. Previous scientific publications have shown that ships contribute significantly to atmospheric concentrations of NOx, particulate matter and ozone. Especially in the case of particulate matter and ozone, this influence can even be seen in regions far away from the main shipping routes. In order to quantify the effects of North Sea shipping on air quality in its bordering states, it is essential to determine the emissions from shipping as accurately as possible. Within Interreg IVb project Clean North Sea Shipping (CNSS), a bottom-up approach was developed and used to thoroughly compile such an emission inventory for 2011 that served as the base year for the current emission situation. The innovative aspect of this approach was to use load-dependent functions to calculate emissions from the ships' current activities instead of averaged emission factors for the entire range of the engine loads. These functions were applied to ship activities that were derived from hourly records of Automatic Identification System signals together with a database containing the engine characteristics of the vessels that traveled the North Sea in 2011. The emission model yielded ship emissions among others of NOx and SO2 at high temporal and spatial resolution that were subsequently used in a chemistry transport model in order to simulate the impact of the emissions on pollutant concentration levels. The total emissions of nitrogen reached 540 Gg and those of sulfur oxides 123 Gg within the North Sea – including the adjacent western part of the Baltic Sea until 5° W. This was about twice as much of those of a medium-sized industrialized European state like the Netherlands. The relative contribution of ships to, for example, NO2 concentration levels ashore close to the sea can reach up to 25 % in summer and 15 % in winter. Some hundred kilometers away from the sea, the contribution was about 6 % in summer and 4 % in winter. The relative contribution of the secondary pollutant NO3− was found to reach 20 % in summer and 6 % in winter even far from the shore.
Observational evidence of temperature trends at two levels in the surface layer
Authors: Lin X. , Pielke Sr. R. A. , Mahmood R. , Fiebrich C. A. , Aiken R.
Published: January 2016

Abstract. Long-term surface air temperatures at 1.5 m screen level over land are used in calculating a global average surface temperature trend. This global trend is used by the IPCC and others to monitor, assess, and describe global warming or warming hiatus. Current knowledge of near-surface temperature trends with respect to height, however, is limited and inadequately understood because surface temperature observations at different heights in the surface layer of the world are rare especially from a high-quality and long-term climate monitoring network. Here we use high-quality two-height Oklahoma Mesonet observations, synchronized in time, fixed in height, and situated in relatively flat terrain, to assess temperature trends and differentiating temperature trends with respect to heights (i.e., near-surface lapse rate trend) over the period 1997 to 2013. We show that the near-surface lapse rate has significantly decreased with a trend of −0.18 ± 0.03 °C (10 m)−1 per decade indicating that the 9 m height temperatures increased faster than temperatures at the 1.5 m screen level and/or conditions at the 1.5 m height cooled faster than at the 9 m height. However, neither of the two individual height temperature trends by themselves were statistically significant. The magnitude of lapse rate trend is greatest under lighter winds at night. Nighttime lapse rate trends were significantly more negative than daytime lapse rate trends and the average lapse rate trend was three times more negative under calm conditions than under windy conditions. Our results provide the first observational evidence of near-surface temperature changes with respect to height that could enhance the assessment of climate model predictions.
Observations of high droplet number concentrations in Southern Ocean boundary layer clouds
Authors: Chubb T. , Huang Y. , Jensen J. , Campos T. , Siems S. , Manton M.
Published: January 2016

Abstract. Cloud physics data collected during the NSF/NCAR High-performance Instrumented Airborne Platform for Environmental Research (HIAPER) Pole-to-Pole Observations (HIPPO) campaigns provide a snapshot of unusual wintertime microphysical conditions in the boundary layer over the Southern Ocean. On 29 June 2011, the HIAPER sampled the boundary layer in a region of pre-frontal warm air advection between 58 and 48° S to the south of Tasmania. Cloud droplet number concentrations were consistent with climatological values in the northernmost profiles but were exceptionally high for wintertime in the Southern Ocean at 100–200 cm−3 in the southernmost profiles. Sub-micron (0.06  < D <  1 µm) aerosol concentrations for the southern profiles were up to 400 cm−3. Analysis of back trajectories and atmospheric chemistry observations revealed that while conditions in the troposphere were more typical of a clean remote ocean airmass, there was some evidence of continental or anthropogenic influence. However, the hypothesis of long-range transport of continental aerosol fails to explain the magnitude of the aerosol and cloud droplet concentration in the boundary layer. Instead, the gale force surface winds in this case (wind speed at 167 m above sea level was  > 25 m s−1) were most likely responsible for production of sea spray aerosol which influenced the microphysical properties of the boundary layer clouds. The smaller size and higher number concentration of cloud droplets is inferred to increase the albedo of these clouds, and these conditions occur regularly, and are expected to increase in frequency, over windy parts of the Southern Ocean.
Understanding the Recent Trend of Haze Pollution in Eastern China: Roles of Climate Change
Authors: Wang H. J. , Chen H. P.
Published: January 2016

Abstract. In this paper, the variation and trend of haze pollution in eastern China for winter of 1960–2012 were analyzed. With the overall increasing number of winter haze days in the period, the five decades were divided into three sub-periods based on the changes of winter haze days (WHD) in central North China (30° N–40° N) and eastern South China (south of 30° N) for east of 109° E mainland China. Results show that WHD kept gradual increasing during 1960–1979, overall stable during 1980–1999, and fast increasing during 2000–2012. The author identified the major climate forcing factors besides total energy consumption. Among all the possible climate factors, variability of the autumn Arctic sea ice extent, local precipitation and surface wind during winter is most influential to the haze pollution change. The joint effect of fast increase of total energy consumption, rapid decline of Arctic sea ice extent and reduced precipitation and surface winds intensified the haze pollution in central North China after 2000. There is similar conclusion for haze pollution in eastern South China after 2000, with the precipitation effect being smaller and spatially inconsistent.
Using critical area analysis to deconvolute internal and external particle variability in heterogeneous ice nucleation
Authors: Beydoun Hassan , Sullivan Ryan C.
Published: January 2016

Abstract. Heterogeneous ice nucleation remains one of the outstanding problems in cloud physics and atmospheric science. Experimental challenges in properly simulating particle induced freezing processes under atmospherically relevant conditions have largely contributed to the absence of a consistent and comprehensive parameterization of immersion freezing properties. Here we formulate an ice active surface site based stochastic model of heterogeneous freezing with the unique feature of invoking a continuum assumption on the ice nucleating activity (contact angle) of an aerosol particle's surface, that requires no assumptions about the size or number of active sites. The result is a particle specific property g that defines a distribution of local ice nucleation rates. Upon integration this yields a full freezing probability function for an ice-nucleating particle. Current cold plate droplet freezing measurements provide a great resource for studying the freezing properties of many atmospheric aerosol systems. A method based on statistical significance to determine an ice nucleating species' specific critical surface area is presented that can resolve the two-dimensional nature of the ice nucleation ability of aerosol particles: internal variability in active site strengths and freezing rates along an individual particle's surface, as well as external variability between two particles of the same type in an aerosol population. By applying this method to experimental data we demonstrate its ability to comprehensively interpret immersion freezing temperature spectra of droplets containing variable particle concentrations. It is shown that general active site density functions such as the popular ns parameterization cannot be reliably extrapolated below this critical area threshold to describe freezing curves for lower particle surface area concentrations. Freezing curves obtained below this threshold translate to higher ns values, while the ns values are essentially the same from curves obtained above the critical area threshold. However, we can successfully predict the lower concentration freezing curves, which are more atmospherically relevant, through a process of random sampling from the statistically significant global distribution obtained from high particle concentration data. Our analysis further revealed that one individual atmospheric illite mineral particle will not contain the entire range of ice active site activity for that system (its internal variability). Comprehensive parameterizations that can predict the temporal evolution of the frozen fraction of cloud droplets in larger atmospheric models are also derived from this new framework.
Vertical wind retrieved by airborne lidar and analysis of island induced gravity waves in combination with numerical models and in-situ particle measurements
Authors: Chouza F. , Reitebuch O. , Jähn M. , Rahm S. , Weinzierl B.
Published: January 2016

Abstract. This study presents the analysis of island induced gravity waves observed by an airborne Doppler wind lidar (DWL) during SALTRACE. First, the instrumental corrections required for the retrieval of high spatial resolution vertical wind measurements from an airborne DWL are presented and the measurement accuracy estimated by means of two different methods. The estimated systematic error is below -0.05 m s-1 for the selected case of study, while the random error lies between 0.1 m s-1 and 0.16 m s-1 depending on the estimation method. Then, the presented method is applied to two measurement flights during which the presence of island induced gravity waves was detected. The first case corresponds to a research flight conducted on 17 June 2013 in the Cape Verde islands region, while the second case corresponds to a measurement flight on 26 June 2013 in the Barbados region. The presence of trapped lee waves predicted by the calculated Scorer parameter profiles was confirmed by the lidar and in-situ observations. The DWL measurements are used in combination with in-situ wind and particle number density measurements, large eddy simulations (LES), and wavelet analysis to determine the main characteristics of the observed island induced trapped waves.
Regional and global climate response to anthropogenic SO2 emissions from China in three climate models
Authors: Kasoar M. , Voulgarakis A. , Lamarque J.-F. , Shindell D. T. , Bellouin N. , Collins W. J. , Faluvegi G. , Tsigaridis K.
Published: January 2016

Abstract. We use the HadGEM3-GA4, CESM1, and GISS ModelE2 climate models to investigate the global and regional aerosol burden, radiative flux, and surface temperature responses to removing anthropogenic sulfur dioxide (SO2) emissions from China. We find that the models differ by up to a factor of six in the simulated change in aerosol optical depth (AOD) and shortwave radiative flux over China that results from reduced sulfate aerosol, leading to a large range of magnitudes in the regional and global temperature responses. Two of the three models simulate a near-ubiquitous hemispheric warming due to the regional SO2 removal, with similarities in the local and remote pattern of response, but overall with a substantially different magnitude. The third model simulates almost no significant temperature response. We attribute the discrepancies in the response to a combination of substantial differences in the chemical conversion of SO2 to sulfate, translation of sulfate mass into AOD, and differences in the radiative forcing efficiency of sulfate aerosol in the models. The model with the strongest response (HadGEM3-GA4) compares best with observations of AOD regionally, however the other two models compare similarly (albeit poorly) and still disagree substantially in their simulated climate response, indicating that total AOD observations are far from sufficient to determine which model response is more plausible. Our results highlight that there remains a large uncertainty in the representation of both aerosol chemistry as well as direct and indirect aerosol radiative effects in current climate models, and reinforces that caution must be applied when interpreting the results of single-model studies of aerosol influences on climate. Model studies that implicate aerosols in climate responses should ideally explore a range of radiative forcing strengths representative of this uncertainty, in addition to thoroughly evaluating the models used against observations.
The adsorption of fungal ice-nucleating proteins on mineral dusts: a terrestrial reservoir of atmospheric ice-nucleating particles
Authors: O'Sullivan Daniel , Murray Benjamin J. , Ross James , Webb Michael E.
Published: January 2016

Abstract. The occurrence of ice-nucleating particles (INPs) in our atmosphere has a profound impact on the properties and lifetime of supercooled clouds. To date, the identities, sources and abundances of particles capable of nucleating ice at relatively low supercoolings (T > −15° C) remain enigmatic. While biomolecules such as proteins and carbohydrates have been implicated as important high-temperature INPs, the lack of knowledge on the environmental fates of these species makes it difficult to assess their potential atmospheric impacts. Here we show that such nanoscale ice nucleating proteins from a common soil borne fungus (Fusarium avenaceum) preferentially bind to and confer their ice-nucleating properties to kaolinite. The ice-nucleating activity of the proteinaceous INPs is unaffected by adsorption to the clay, and once bound the proteins do not readily desorb, retaining much of the activity even after multiple washings with pure water. The atmospheric implications of the finding that biological residues can confer their ice-nucleating ability to dust particles are discussed.
Impact of Siberia forest fires on the atmospheric environment over the Korean Peninsula during summer 2014
Authors: Jung Jinsang , Lyu Youngsook , Lee Minhee , Hwang Taekyung , Hong Youdeok , Hong Jihyung , Lee Sangi , Oh Sanghyub
Published: January 2016

Abstract. Extensive forest fires occurred during the late July, 2014 across the Siberia forest region, Russia. Smoke plumes emitted from the Siberia forest fires were long-range transported through Mongolia and northeast China, and down to the Korean Peninsula, which is located at ~3,000 km south of the Siberia forest. Notably high aerosol optical depth (AOD) of ~4 was observed at a wavelength of 500 nm near the source region of the Siberia forest fires. The smoke plumes reached about 3–5 km height near the source region and then below 2 km height near the Korean Peninsula. Elevated concentration of levoglucosan was observed as an average of 119.7 ± 6.0 ng m-3 (mean ± one standard deviation) which was ~4.5 times higher than those observed during the non-event period in July, 2014. During the middle of July 2014, another type of haze episode occurred that was mainly caused by long-range transported haze plumes originated from urban and industrial complexes in the East China. Sharp increases in SO42- concentrations (23.1 ± 2.1 μg m-3) were observed during the Chinese haze episode. The haze episode caused by the long-range transported Siberia forest fires was clearly distinguished with relatively high OC/EC ratio (7.18 ± 0.2) and OC/SO42- ratio (1.31 ± 0.07) compared to those (OC/EC ratio: 2.4 ± 0.4, OC/SO42- ratio: 0.21 ± 0.05) during the Chinese haze episode. Remote measurement techniques and chemical analyses of the haze plumes clearly showed that the haze episode occurred during the late July, 2014 was mainly caused by the long-range transported smoke plumes emitted from Siberia forest fires.
Estimation of the advection effects induced by surface heterogeneities in the surface energy budget
Authors: Cuxart J. , Wrenger B. , Martínez-Villagrasa D. , Reuder J. , Jonassen M.O. , Jiménez M.A. , Lothon M. , Lohou F. , Hartogensis O. , Dünnermann J. , Conangla L. , Garai A.
Published: January 2016

Abstract. The effect of terrain heterogeneities in one-point measurements is a continuous subject of discussion. Here we focus on the order of magnitude of the advection term in the equation of the temperature as generated by documented terrain heterogeneities and we estimate its importance as a term in the surface energy budget (SEB). The heterogeneities are estimated from satellite and model fields for scales near 1 kilometer or broader, while the smaller scales are estimated through direct measurements with remotely-piloted aircraft, thermal cameras and also by high-resolution modeling. The variability of the surface temperature fields is not found to decrease clearly with increasing resolution, and consequently the advection term becomes more important as the scales become finer. The advection term provides non-significant values to the SEB at scales larger than few kilometers. On the contrary, surface heterogeneities at the meter scale yield large values of the advection, which are probably only significant in the first centimeters above the ground. The motions that seem to contribute significantly to the advection term in the SEB equation in our case are roughly those around the hectometer scales.
Assessment of fire emissions inventories during the South American Biomass Burning Analysis (SAMBBA) experiment
Authors: Pereira G. , Siqueira R. , Rosário N. E. , Longo K.L. , Freitas S .R. , Cardozo F. S. , Kaiser J. W. , Wooster M. J.
Published: January 2016

Abstract. Fires associated with land use and land cover changes release into the atmosphere large amounts of aerosols and trace gases. Although there are several inventories of biomass burning emissions covering Brazil, there are still considerable uncertainties and differences among these. While most fire emissions inventories still utilize the parameters of vegetation fuel load, emission factors and other parameters to estimate the biomass burned and its associated emissions, certain more recent inventories tend to apply an alternative method based on fire radiative power (FRP) observations to estimate the amount of biomass burned and the corresponding emissions of trace gases and aerosols. The Brazilian Biomass Burning Emission Model (3BEM) and Fire Inventory from NCAR (FINN) are examples of the first, while Brazilian Biomass Burning Emission Model with FRP assimilation (3BEM_FRP) and Global Fire Assimilation System (GFAS) are examples of the latter method mentioned. In this paper, the output of four biomass burning emission inventories used during the South American Biomass Burning Analysis (SAMBBA) field campaign are analyzed and intercompared, focusing on eight predefined grids. Aerosol optical thickness derived from measurements made by the MODIS sensor operating onboard the Aqua satellite is applied to assess the inventories consistency. Significant correlation coefficients (r, p>0.05 level, Student t-test) were found between 3BEM and FINN, and between 3BEM_FRP and GFAS, with approximately 0.86 and 0.85, respectively. These results indicate that emissions estimates in this region derived via similar methods tend to agree with one other, but differ more from the estimates derived via the alternative approach. However, correlations in specific grids indicate that 3BEM and FINN typically underestimated the smoke emission loading in the eastern region of Amazon Forest, whilst 3BEM_FRP presents a tendency to overestimate fire emissions in the same area. The relationship between the 3BEM and FINN fire inventories present a correlation coefficient of 0.75-0.92, with a tendency of FINN to overestimate the emission of carbon monoxide by 20-30%. Moreover, 3BEM and GFAS shows a correlation coefficient of between 0.75-0.85, with higher values near the arc of deforestation in Amazon Rainforest. However, GFAS has a tendency to present higher carbon monoxide emissions in this region, and 3BEM_FRP tends to overestimate the emissions in soybean expansion (east of Amazon forest).