bluuebunny/crossref_metadata_2025 huggingface dataset:
Synoptic meteorological modes of variability for fine particulate matter (PM2.5) air quality in major metropolitan regions of China
Authors: Leung Danny M. , Tai Amos P. K. , Mickley Loretta J. , Moch Jonathan M. , van Donkelaar Aaron , Shen Lu , Martin Randall V.
Published: May 2018

Abstract. In his study, we use a combination of multivariate statistical methods to
understand the relationships of PM2.5 with local meteorology and
synoptic weather patterns in different regions of China across various
timescales. Using June 2014 to May 2017 daily total PM2.5 observations
from ∼ 1500 monitors, all deseasonalized and detrended to focus
on synoptic-scale variations, we find strong correlations of daily PM2.5
with all selected meteorological variables (e.g., positive correlation with
temperature but negative correlation with sea-level pressure throughout
China; positive and negative correlation with relative humidity in northern
and southern China, respectively). The spatial patterns suggest that the
apparent correlations with individual meteorological variables may arise from
common association with synoptic systems. Based on a principal component
analysis of 1998–2017 meteorological data to diagnose distinct
meteorological modes that dominate synoptic weather in four major regions of
China, we find strong correlations of PM2.5 with several synoptic modes
that explain 10 to 40 % of daily PM2.5 variability. These modes
include monsoonal flows and cold frontal passages in northern and central
China associated with the Siberian High, onshore flows in eastern China, and
frontal rainstorms in southern China. Using the Beijing–Tianjin–Hebei (BTH)
region as a case study, we further find strong interannual correlations of
regionally averaged satellite-derived annual mean PM2.5 with annual mean
relative humidity (RH; positive) and springtime fluctuation frequency of the
Siberian High (negative). We apply the resulting PM2.5-to-climate
sensitivities to the Intergovernmental Panel on Climate Change (IPCC) Coupled
Model Intercomparison Project Phase 5 (CMIP5) climate projections to predict
future PM2.5 by the 2050s due to climate change, and find a modest
decrease of ∼ 0.5 µg m−3 in annual mean
PM2.5 in the BTH region due to more frequent cold frontal ventilation
under the RCP8.5 future, representing a small “climate benefit”, but the
RH-induced PM2.5 change is inconclusive due to the large inter-model
differences in RH projections.
A new index for the wintertime southern hemispheric split jet
Authors: Babian Stella , Grieger Jens , Cubasch Ulrich
Published: May 2018

Abstract. One of the most prominent asymmetric features of the southern
hemispheric (SH) circulation is the split jet over Australia and New Zealand
in austral winter. Previous studies have developed indices to detect the
degree to which the upper-level midlatitude westerlies are split and
investigated the relationship between split events and the low-frequency
teleconnection patterns, viz. the Antarctic Oscillation (AAO) and the El
Niño–Southern Oscillation (ENSO). As the results were inconsistent, the
relationship between the wintertime SH split jet and the climate variability
indices remains unresolved and is the focus of this study. Until now, all split indices' definitions were based on the specific region where
the split jet is recognizable. We consider the split jet as hemispheric rather
than a regional feature and propose a new, hemispherical index that is based on
the principal components (PCs) of the zonal wind field for the SH winter. A
linear combination of PC2 and PC3 of the anomalous monthly (JAS) zonal wind is
used to identify split-jet conditions. In a subsequent correlation analysis, our newly defined PC-based split index (PSI) indicates
a strong coherence with the AAO. However, this significant relationship is
unstable over the analysis period; during the 1980s, the AAO amplitude was
higher than the PSI, and vice versa in the 1990s. It is probable that the PSI,
as well as the AAO, underlie low-frequency variability on the decadal to
centennial timescales, but the analyzed period is too short to draw these
conclusions. A regression analysis with the Multivariate ENSO Index points to
a nonlinear relationship between PSI and ENSO; i.e., split jets occur during
both strong positive and negative phases of ENSO but rarely under “normal”
conditions. The Pacific South American (PSA) patterns, defined as the second and third modes of the
geopotential height variability at 500 hPa, correlate poorly with the PSI
(rPSA−1 ≈ 0.2 and rPSA-2= 0.06), but
significantly with the individual components (PCs) of the PSI, revealing an
indirect influence on the SH split-jet variability. Our study suggests that the wintertime SH split jet is strongly associated with
the AAO, while ENSO is to a lesser extent connected to the PSI. We conclude that
a positive AAO phase, as well as both flavors of ENSO and the PSA-1 pattern
produce favorable conditions for a SH split event.
Aerosol pH and its influencing factors in Beijing
Authors: Ding Jing , Zhao Pusheng , Su Jie , Dong Qun , Du Xiang
Published: May 2018

Abstract. Acidity (pH) plays a key role in the physical and chemical behavior of aerosol and cannot be measured directly. In this work, aerosol liquid water content (ALWC) and size-resolved pH are predicted by thermodynamic model (ISORROPIA-II) in 2017 of Beijing. The mean aerosol pH over four seasons is 4.3±1.6 (spring), 4.5±1.1 (winter), 3.9±1.3 (summer), 4.1±1.0 (autumn), respectively, showing the moderate aerosol acidity. The aerosol pH in fine mode is in the range of 1.8 ~ 3.9, 2.4 ~ 6.3 and 3.5 ~ 6.5 for summer, autumn and winter, respectively. And coarse particles are generally neutral or alkaline. Diurnal variation of aerosol pH follows both aerosol components (especially the sulfate) and ALWC. For spring, summer and autumn, the averaged nighttime pH is 0.3~0.4 unit higher than that on daytime. Whereas in winter, the aerosol pH is relatively low at night and higher at sunset. SO42− and RH are two crucial factors affecting aerosol pH. For spring, winter and autumn, the effect of SO42− on aerosol pH is greater than RH, and it is comparable with RH in summer. The aerosol pH decreases with elevated SO42− concentration. As the NO3− concentration increases, the aerosol pH firstly increases and then decreases. Sulfate-dominant aerosols are more acidic with pH lower than 4, whereas nitrate-dominated aerosols are weak in acidity with pH ranges 3~5. In recent years, the dominance of NO3− in inorganic ions may be another reason responsible for the moderately acidic aerosol. ALWC has a different effect on aerosol pH in different seasons. In winter, the increasing RH could reduce the aerosol pH whereas it shows a totally reverse tendency in summer, and the elevated RH has little effect on aerosol pH in spring and autumn when the RH is between 30 % and 80 %. The dilution effect of ALWC on Hair+ is only obvious in summer. The elevated NH3 and NH4+ could reduce aerosol acidity by decreasing Hair+ concentration exponentially.
Atmospheric Δ17O(NO3−) reveals nocturnal chemistry dominates nitrate production in Beijing haze
Authors: He Pengzhen , Xie Zhouqing , Chi Xiyuan , Yu Xiawei , Fan Shidong , Kang Hui , Liu Cheng , Zhan Haicong
Published: May 2018

Abstract. The rapid mass increase of atmospheric nitrate is a critical driving force for the occurrence of fine-particle pollution (referred to as haze hereafter) in Beijing. However, the exact mechanisms for this rapid increase of nitrate mass has been not well constrained from field observations. Here we present the first observations of the oxygen-17 excess of atmospheric nitrate (Δ17O(NO3−)) collected in Beijing haze to reveal the relative importance of different nitrate formation pathways, and we also present the simultaneously observed δ15N(NO3−). During our sampling period, 12 h-averaged mass concentrations of PM2.5 varied from 16 to 323 μg m−3 with a mean of (141 ± 88 (1σ)) μg m−3, with nitrate ranging from 0.3 to 106.7 μg m−3. The observed Δ17O(NO3−) ranged from 27.5 ‰ to 33.9 ‰ with a mean of (30.6 ± 1.8) ‰ while δ15N(NO3−) ranged from −2.5 ‰ to 19.2 ‰ with a mean of (7.4 ± 6.8) ‰. Δ17O(NO3−)-constrained calculations suggest nocturnal pathways (N2O5 + H2O/Cl− and NO3 + HC) dominated nitrate production during polluted days (PM2.5 ≥ 75 μg m−3) with the mean possible fraction of 56 − 97 %. For δ15N(NO3−), we found that a combined effect of variability in NOX sources and isotopic exchange between NO and NO2 is likely to be most responsible for its variations. Our results illustrate the potentiality of isotope in tracing NOX sources and nitrate formation pathways, future modelling work with the constraint of isotope data reported here may further improve our understanding of nitrogen cycle during haze.
Undulating wave front of mesospheric bore; Space-borne observations by ISS-IMAP/VISI
Authors: Hozumi Yuta , Saito Akinori , Sakanoi Takeshi , Yamazaki Atsushi , Hosokawa Keisuke
Published: May 2018

Abstract. Large-scale spatial structures of mesospheric bores were observed by Visible and near Infrared Spectral Imager (VISI) of the ISS-IMAP mission (Ionosphere, Mesosphere, upper Atmosphere and Plasmasphere mapping mission from the International Space Station) in the mesospheric O2 airglow at 762 nm wavelength. Two mesospheric bore events are reported in this paper; one event was observed over the south of African continent (48° S–54° S and 10° E–25° E) on 9 July 2015, and the other event over the south Atlantic Ocean (35° S–43° S and 24° W–1° E) on 7 May 2013. For the first event, the temporal evolution of the mesospheric bore was investigated from the difference of two observations in consecutive paths. The estimated eastward speed of the bore is 100 m/sec. The number of trailing waves increased with a rate of 3.5 wave/hour. Anti-clockwise rotation with a speed of 20º/hour was also recognized. These parameters are similar to those reported by previous studies based on ground-based measurements, and the similarity supports the validity of VISI observation for mesospheric bores. For the second event, VISI captured a mesopshric bore having a large-scale and undulating wave front. The horizontal extent of the wave front was 2,200 km. The long wave front undulated with 1,000 km wave length. The undulating wave front is a new feature of mesospheric bore revealed by the wide FOV of VISI. We suggest that non-uniform bore propagating speed due to inhomogeneous background ducting structure might be a cause of the undulation of the wave front. Temperature measurements from the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) of the Thermosphere, Ionosphere, Mesosphere, Energetics and Dynamics (TIMED) satellite indicated that bores of both events were ducted in a temperature inversion layer.
Insights into HOX and ROX chemistry in the boreal forest via measurement of peroxyacetic acid, peroxyacetic nitric anhydride (PAN) and hydrogen peroxide
Authors: Crowley John N. , Pouvesle Nicolas , Phillips Gavin J. , Axinte Raoul , Fischer Horst , Petäjä Tuukka , Nölscher Anke , Williams Jonathan , Hens Korbinian , Harder Hartwig , Martinez-Harder Monica , Novelli Anna , Kubistin Dagmar , Bohn Birger , Lelieveld Jos
Published: May 2018

Abstract. Unlike many oxidised atmospheric trace gases, which have numerous production pathways, peroxyacetic acid (PAA) and PAN are formed almost exclusively in gas-phase reactions involving the hydroperoxy radical (HO2), the acetyl peroxy radical (CH3C(O)O2) and NO2 and are not believed to be directly emitted in significant amounts by vegetation. As the self-reaction of HO2 is the main photochemical route to hydrogen peroxide (H2O2), simultaneous observation of PAA, PAN and H2O2 can provide insight into the HO2 budget. We present an analysis of observations taken during a summertime campaign in a boreal forest that, in addition to natural conditions, was temporarily impacted by two biomass burning plumes. The observations were analysed using an expression based on a steady-state assumption using relative PAA-to-PAN mixing ratios to derive HO2 concentrations. The steady-state approach generated HO2 concentrations that were generally in reasonable agreement with measurements but sometimes overestimated those observed by factors of two or more. We also used a chemically simple, constrained box-model to analyse the formation and reaction of radicals that define the observed mixing ratios of PAA, H2O2. After nudging the simulation towards observations by adding extra, photochemical sources of HO2 and CH3C(O)O2, the box model replicated the observations of PAA, H2O2, ROOH and OH throughout the campaign, including the biomass-burning influenced episodes during which significantly higher levels of many oxidized trace gases were observed. The model indicates that organic peroxy radicals were present at night in high concentrations that sometimes exceeded those predicted for daytime. A dominant fraction of CH3O2 radical generation was found to arise via reactions of the CH3C(O)O2 radical. Initially divergent measured and modelled HO2 concentrations and daily concentration profiles are reconciled when these organic peroxy radicals are detected (as HO2) at an efficiency of 35 %. The organic peroxy radicals are found to play an important role in the recycling of OH radicals subsequent to their loss via reactions with volatile organic compounds.
Understanding aerosol–cloud interactions
through modelling the
development of orographic cumulus congestus during IPHEx
Authors: Duan Yajuan , Petters Markus D. , Barros Ana P.
Published: May 2018

Abstract. A new cloud parcel model (CPM) including activation, condensation, collision-coalescence, and lateral entrainment processes is presented here to investigate aerosol-cloud interactions (ACI) in cumulus development prior to rainfall onset. The CPM was applied with surface aerosol measurements to predict the vertical structure of cloud development at early stages, and the model results were compared with airborne observations of cloud microphysics and thermodynamic conditions collected during the Integrated Precipitation and Hydrology Experiment (IPHEx) in the inner region of the Southern Appalachian Mountains (SAM). Sensitivity analysis was conducted to examine the model response to variations in key ACI physical parameters. The condensation coefficient ac plays a governing role in determining the cloud droplet number concentration (CDNC), liquid water content (LWC), and droplet size distribution. Lower values of ac lead to higher cloud droplet number concentrations, broader droplet spectra, and higher maximum supersaturation near cloud base. The simulated vertical structure of CDNC exhibits strong nonlinear sensitivity to entrainment strength and condensation efficiency illustrative of competitive interference between turbulent dispersion and activation processes. Further, simulated CDNC exhibits high sensitivity to variations in initial aerosol concentration at cloud base, but weak sensitivity to aerosol hygroscopicity. These findings provide new insights into determinant factors of convective cloud formation leading to mid-day warm season rainfall in complex terrain.
Intra-pixel variability in satellite tropospheric NO2 column densities derived from simultaneous space-borne and airborne observations over the South African Highveld
Authors: Broccardo Stephen , Heue Klaus-Peter , Walter David , Meyer Christian , Kokhanovsky Alexander , van der A Ronald , Piketh Stuart , Langerman Kristy , Platt Ulrich
Published: May 2018

Abstract. Aircraft measurements of NO2 using an imaging differential optical absorption spectrometer (iDOAS) instrument over the South African Highveld region in August 2007 are presented and compared to satellite measurements from OMI and SCIAMACHY. In situ aerosol and trace-gas vertical profile measurements, along with aerosol optical thickness and single-scattering albedo measurements from the Aerosol Robotic Network (AERONET), are used to devise scenarios for a radiative transfer modelling sensitivity study. Uncertainty in the air-mass factor due to variations in the aerosol and NO2 profile shape is constrained and used to calculate vertical column densities (VCDs), which are compared to co-located satellite measurements. The lower spatial resolution of the satellites cannot resolve the detailed plume structures revealed in the aircraft measurements. The airborne DOAS in general measured steeper horizontal gradients and higher peak NO2 vertical column density. Aircraft measurements close to major sources, spatially averaged to the satellite resolution, indicate NO2 column densities more than twice those measured by the satellite. The agreement between the high-resolution aircraft instrument and the satellite instrument improves with distance from the source, this is attributed to horizontal and vertical dispersion of NO2 in the boundary layer. Despite the low spatial resolution, satellite images reveal point sources and plumes that retain their structure for several hundred kilometres downwind.
A new method to
identify flux ropes
in space plasmas
Authors: Huang Shiyong , Zhao Pufan , He Jiansen , Yuan Zhigang , Zhou Meng , Fu Huishan , Deng Xiaohua , Pang Ye , Wang Dedong , Yu Xiongdong , Li Haimeng , Torbert Roy , Burch James
Published: May 2018

Abstract. Flux ropes are frequently observed in the space plasmas, such as magnetosphere, magnetosheath, and solar wind etc., and play an important role in the reconnection process and mass and flux transportation. One usually used bipolar signature and strong core field to identify the flux ropes. We propose here one new method to identify flux ropes based on the correlations between the variables of the data from in-situ spacecraft observations and the target-function-to-be-correlated (TFC) from the ideal flux rope model. Through comparing the correlation coefficients of different variables at different time and scales, and performing weighted average technique, this method can derive the scales and locations of the flux ropes. We discuss the limitation of our method and also compare it with other methods.
Drainage reorganization and divide migration induced by the excavation of the Ebro basin (NE Spain)
Authors: Vacherat Arnaud , Bonnet Stéphane , Mouthereau Frédéric
Published: May 2018

Abstract. Intracontinental endorheic basins are key elements of source-to-sink systems as they preserve sediments eroded from the surrounding catchments. Drainage reorganization in such a basin in response to changing boundary conditions has strong implications on the sediment routing system and on landscape evolution. The Ebro and Duero basins represent two foreland basins, which developed in response to the growth of surrounding compressional orogens, the Pyrenees and the Cantabrian mountains to the north, the Iberian Ranges to the south, and the Catalan Coastal Range to the east. They were once connected as endorheic basins in the early Oligocene. By the end of the Miocene, new post-orogenic conditions led to the current setting in which the Ebro and Duero basins are flowing in opposite directions, towards the Mediterranean Sea and the Atlantic Ocean. Although these two hydrographic basins recorded a similar history, they are characterized by very different morphologic features. The Ebro basin is highly excavated, whereas relicts of the endorheic stage are very well preserved in the Duero basin. The contrasting morphological preservation of the endorheic stage represents an ideal natural laboratory to study the drivers (internal and/or external) of post-orogenic drainage divide mobility, drainage network, and landscape evolution. To that aim, we use field and map observations and we apply the χ analysis of river profiles along the divide between the Ebro and Duero drainage basins. We show here that the contrasting excavation of the Ebro and Duero basins drives a reorganization of their drainage network through a series of captures, which resulted in the southwestward migration of their main drainage divide. Fluvial captures have a strong impact on drainage areas, fluxes, and their respective incision capacity. We conclude that drainage reorganization driven by the capture of the Duero basin rivers by the Ebro drainage system explains the first-order preservation of endorheic stage remnants in the Duero basin, due to drainage area loss, independently from tectonics and climate.
Cohesive and mixed sediment in the Regional Ocean Modeling System (ROMS v3.6) implemented in the Coupled Ocean–Atmosphere–Wave–Sediment Transport Modeling System (COAWST r1234)
Authors: Sherwood Christopher R. , Aretxabaleta Alfredo L. , Harris Courtney K. , Rinehimer J. Paul , Verney Romaric , Ferré Bénédicte
Published: May 2018

Abstract. We describe and demonstrate algorithms for treating cohesive and mixed sediment that have been added to the Regional Ocean Modeling System (ROMS version 3.6), as implemented in the Coupled Ocean–Atmosphere–Wave–Sediment Transport Modeling System (COAWST Subversion repository revision 1234). These include the following: floc dynamics (aggregation and disaggregation in the water column); changes in floc characteristics in the seabed; erosion and deposition of cohesive and mixed (combination of cohesive and non-cohesive) sediment; and biodiffusive mixing of bed sediment. These routines supplement existing non-cohesive sediment modules, thereby increasing our ability to model fine-grained and mixed-sediment environments. Additionally, we describe changes to the sediment bed layering scheme that improve the fidelity of the modeled stratigraphic record. Finally, we provide examples of these modules implemented in idealized test cases and a realistic application.
STORM: A simple, flexible, and parsimonious stochastic rainfall generator for simulating climate and climate change
Authors: Singer Michael Bliss , Michaelides Katerina , Hobley Daniel E. J.
Published: May 2018

Abstract. Assessments of water balance, watershed response, and landscape evolution to climate change require representation of spatially and temporally varying rainfall fields over a drainage basin, as well as the flexibility to simply modify key driving climate variables (evaporative demand, overall wetness, storminess). An empirical-stochastic approach to the problem of rainstorm simulation enables statistical realism and the creation of multiple ensembles that allow for statistical characterization and/or time series of the driving rainfall over a fine grid for any climate scenario. Here we provide detail on the STOchastic Rainfall Model (STORM), which uses this approach to simulate drainage basin rainfall. STORM simulates individual storms based on Monte Carlo selection from probability density functions (PDFs) of storm area, storm duration, storm intensity at the core, and storm center location. The model accounts for seasonality, orography, and the probability of storm intensity for a given storm duration. STORM also generates time series of potential evapotranspiration (PET), which are required for most physically based applications. We explain the how the model works and demonstrate its ability to simulate observed historical rainfall characteristics for a small watershed in SE Arizona. We explain the data requirements for STORM and its flexibility for simulating rainfall for various classes of climate change. Finally, we discuss several potential applications of STORM.
Estimating long-term groundwater storage and its controlling
factors in cold regions
Authors: Bhanja Soumendra N. , Zhang Xiaokun , Wang Junye
Published: May 2018

Abstract. Groundwater is one of the most important natural resources for economic development and environmental sustainability. However, groundwater storage can be significantly affected by climate change through permafrost thaw, snowpack change, and glacier retreat in cold climate regions, and human activities due to over-use and over-extraction of resources. Therefore, it is very important to be able to estimate long-term groundwater storage for biodiversity and sustainable development. In this study, we estimated groundwater storage in 11 major river basins across Alberta, Canada using a combination of remote sensing (Gravity Recovery and Climate Experiment-GRACE), in situ surface water data, and land surface modelling estimates (GWSAsat). We applied separate calculations for unconfined and confined aquifers, for the first time, to represent their hydrogeological differences. Storage coefficients for the individual wells were incorporated to compute the monthly GWSAobs. The GWSAsat from the two satellite-based products were compared with in situ groundwater storage (GWSAobs) estimates. The estimates of GWSAsat were in good agreement with the GWSAobs in terms of pattern and magnitude (e.g., RMSE ranged from 2 to 14 cm). While comparing GWSAsat with GWSAsat, most of the statistical analyses provide mixed responses, however the Hodrick-Presscott trend analysis clearly showed a better performance of the GRACE-mascon estimate. The results showed trends of GWSAobs depletion in 5 of the 11 basins. Our results indicate that the precipitation played an important role in influencing the GWSAobs variation in 4 of the 11 basins studied. Water budget analysis showed an availability of comparatively lower terrestrial water in 9 of the 11 basins in the study period. Historical groundwater recharge estimates indicate a reduction of groundwater recharge in 8 basins during 1960–2009. The output of this study could be used to develop sustainable water withdrawal strategies in Alberta, Canada.
Rainfall-Runoff modelling using Long-Short-Term-Memory (LSTM) networks
Authors: Kratzert Frederik , Klotz Daniel , Brenner Claire , Schulz Karsten , Herrnegger Mathew
Published: May 2018

Abstract. Rainfall-runoff modelling is one of the key challenges in the field of hydrology. Various approaches exist, ranging from physically based over conceptual to fully data driven models. In this paper, we propose a novel data driven approach, using the Long-Short-Term-Memory (LSTM) network, a special type of recurrent neural networks. The advantage of the LSTM is its ability to learn long-term dependencies between the provided input and output of the network, which are essential for modelling storage effects in e.g. catchments with snow influence. We use 241 catchments of the freely available CAMELS data set to test our approach and also compare the results to the well-known Sacramento Soil Moisture Accounting Model (SAC-SMA) coupled with the Snow-17 snow routine. We also show the potential of the LSTM as a regional hydrological model, in which one model predicts the discharge for a variety of catchments. In our last experiment, we show the possibility to transfer process understanding, learned at regional scale, to individual catchments and thereby increasing model performance when compared to a LSTM trained only on the data of single catchments. Using this approach, we were able to achieve better model performance as the SAC-SMA + Snow-17, which underlines the potential of the LSTM for hydrological modelling applications.
Mapping individuals' earthquake preparedness in China
Authors: Wu Guochun , Han Ziqiang , Xu Weijin , Gong Yue
Published: May 2018

Abstract. Disaster preparedness is critical for reducing potential impact. This paper contributes to current knowledge of disaster preparedness using representative national sample data from China, which faces high earthquake risks in many areas of the country. The adoption of earthquake preparedness activities by the general public, including five indicators of material preparedness and five indicators of awareness preparedness, were surveyed and 3245 respondents from all 31 provinces of Mainland China participated in the survey. Linear regression models and logit regression models were used to analyze the effects of potential influencing factors. Overall, the preparedness levels are not satisfied, with a material preparation score of 3.02 (1–5), and awareness preparation score of 2.79 (1–5), nationally. Meanwhile, residents from western China, which has higher earthquake risk, have higher degrees of preparedness. The concern for disaster risk reduction (DRR) and the concern for building safety and participation in public affairs are consistent positive predictors of both material and awareness preparedness. The demographic and socioeconomic variables' effects, such as gender, age, education, income, urban/rural division, and building size, vary according to different preparedness activities. Finally, the paper concludes with a discussion of the theoretical contribution and potential implementation.
Mean circulation and EKE distribution in the Labrador Sea
Water level of the subpolar North Atlantic
Authors: Fischer Jürgen , Karstensen Johannes , Oltmanns Marilena , Schmidtko Sunke
Published: May 2018

Abstract. A long term mean flow field for the subpolar North Atlantic region with a horizontal resolution of approximately 25 km is created by gridding Argo-derived velocity vectors using two different topography following interpolation schemes. The 10-d float displacements in the typical drift depths of 1000 m to 1500 m represent the flow in the Labrador Sea Water density range. Both mapping algorithms separate the flow field into potential vorticity (PV) conserving, i.e. topography following contribution and a deviating part, which we define as the eddy contribution. To verify the significance of the separation, we compare the mean flow and the eddy kinetic energy (EKE), derived from both mapping algorithms, with those obtained from multiyear mooring observations. The PV-conserving mean flow is characterized by stable boundary currents along all major topographic features including shelf breaks and basin-interior topographic ridges such as the Reykjanes Ridge or the Rockall Plateau. Mid-basin northward advection pathways from the northeastern Labrador Sea into the Irminger Sea and from the Mid Atlantic Ridge region into the Iceland basin are well-resolved. An eastward flow is present across the southern boundary of the subpolar gyre near 52° N, the latitude of the Charlie Gibbs Fracture Zone. The mid-depth EKE field resembles most of the satellite-derived surface EKE field. However, noticeable differences exist along the northward advection pathways in the Irminger Sea and the Iceland basin, where the deep EKE exceeds the surface EKE field. Further, the ratio between mean flow and the square root of the EKE, the Peclet Number, reveals distinct advection-dominated regions as well as basin interior regimes in which mixing is prevailing.
Satellite ice extent, sea surface temperature, and atmospheric methane trends in the Barents and Kara seas
Authors: Leifer Ira , Chen F. Robert , McClimans Thomas , Muller Karger Frank , Yurganov Leonid
Published: May 2018

Abstract. Long-term (2003–2015) satellite-derived sea-ice extent, sea surface temperature (SST), and lower tropospheric methane (CH4) of the Barents and Kara Seas (BKS) were analyzed for statistically significant anomalies and trends for 10 focus areas and on a pixel basis that were related to currents and bathymetry. Large positive CH4 anomalies were discovered around Franz Josef Land (FJL) and offshore west Novaya Zemlya in September. Far smaller CH4 enhancement was around Svalbard, downstream of known seabed seepage. Strongest SST increase was southeast Barents Sea in June due to strengthening of the warm Murman Current (MC) and in the south Kara Sea in September, when the cold Percey Current weakens. These regions and around FJL exhibit the strongest CH4 growth. Likely sources are CH4 seepage from subsea permafrost and hydrates and the petroleum reservoirs underlying the central and east Barents Sea and the Kara Sea. The spatial pattern was poorly related to depth, and better explained by shoaling. Peak CH4 anomaly is several months after peak SST, consistent with a several month delay between SST and seabed temperature. Continued MC strengthening will increase heat transfer to the BKS, rendering the Barents Sea ice-free in about 15 years.
Modeling the response of Greenland outlet glaciers to global
warming using a coupled flowline-plume model
Authors: Beckmann Johanna , Perrette Mahé , Beyer Sebastian , Calov Reinhard , Willeit Matteo , Ganopolski Andrey
Published: May 2018

Abstract. In recent decades, the Greenland Ice Sheet has experienced an accelerated mass loss, contributing to approximately 25 % of contemporary sea level rise. This mass loss is caused by increased surface melt over a large area of the ice sheet and by the thinning, retreat and acceleration of numerous Greenland outlet glaciers. The latter is likely connected to enhanced submarine melting that, in turn, can be explained by ocean warming and enhanced subglacial discharge. The mechanisms involved in submarine melting are not yet fully understood and are only crudely incorporated in some models of the Greenland Ice Sheet. Here, we investigate the response of twelve representative Greenland outlet glaciers to atmospheric and oceanic warming using a coupled 1D line-plume glacier-flowline model. The model parameters have been tuned for individual outlet glaciers using present-day observational constraints. We then run the model from present to the year 2100, forcing the model with changes in surface mass balance and surface runoff from simulations with a regional climate model for the RCP 8.5 scenario, and applying a linear ocean temperature warming with different rates of changes representing uncertainties in the CMIP 5 model experiments for the same climate change scenario. We also used different initial temperature-salinity profiles obtained from direct measurements and from ocean reanalysis data. Using different combinations of submarine melting and calving parameters that reproduce the present-day state of the glaciers, we estimated uncertainties in the contribution to global sea level rise for individual glaciers. We also performed a factor analysis, which shows that the role of different forcing (change in surface mass balance, ocean temperature and subglacial discharge) are diverse for individual glaciers. We found that changes in, ocean temperature and subglacial discharge are of comparable importance for the cumulative contribution of all twelve glaciers to global sea level rise in the 21st century. The median range of the cumulative contribution to the global sea level rise for all twelve glaciers is about 14 mm from which roughly 85 % are associated with the response to increased submarine melting and the remaining part to surface mass loss. We also found a weak correlation (correlation coefficient 0.35) between present-day grounding line discharge and their future contribution to sea level rise in 2100. If the contribution of the twelve glaciers is scaled up to the total present-day discharge of Greenland, we estimate the contribution of all Greenland glaciers to 21st-century sea level rise to be approximately 50 mm. This result confirms earlier studies that the response of the outlet glaciers to global warming has to be taken into account to correctly assess the total contribution of Greenland to sea level change.
Control-oriented Linear Dynamic Wind Farm Flow and Operation
Model
Authors: Kazda Jonas , Cutululis Nicolaos Antonio
Published: May 2018

Abstract. The use of dynamic wind farm flow models is beneficial for power reference following wind farm control. However, currently investigated flow models are non-linear and computationally expensive, while common control approaches require fast, linear models. This work presents a novel wind farm operation modelling approach named the Dynamic Flow Predictor. The Dynamic Flow Predictor was developed with the objective to provide predictions of wind speed and turbine power using a computationally effective, linear, dynamic state space model. The model estimates wind turbine aerodynamic interaction using a linearized engineering wake model in combination with a delay process. Simulations of two turbines and eight turbines in SimWindFarm show that the Dynamic Flow Predictor can provide accurate estimates and predictions of wind turbine rotor effective wind speed and power. Additionally, the Dynamic Flow Predictor is computationally effective as it requires only 5 % of the states of a comparable, dynamic 2D CFD model. The presented modelling approach is thus well suited for the use in wind farm control, while it is envisioned that the model can also be useful for wind turbine control and as a virtual wind turbine sensor.
A simulation study demonstrating the importance of large-scale trailing vortices in wake steering
Authors: Fleming Paul , Annoni Jennifer , Churchfield Matthew , Martinez-Tossas Luis A. , Gruchalla Kenny , Lawson Michael , Moriarty Patrick
Published: May 2018

Abstract. In this paper, we investigate the role of flow structures generated in wind
farm control through yaw misalignment. A pair of counter-rotating vortices is
shown to be important in deforming the shape of the wake and in explaining
the asymmetry of wake steering in oppositely signed yaw angles. We also
demonstrate that vortices generated by an upstream turbine that is performing
wake steering can deflect wakes of downstream turbines, even if they are
themselves aligned. We encourage the development of improvements to control-oriented engineering
models of wind farm control, to include the effects of these large-scale flow
structures. Such a new model would improve the predictability of
control-oriented models. Further, we demonstrate that the vortex structures
created in wake steering can lead to greater impact on power generation than
currently modeled in control-oriented models. We propose that wind farm
controllers can be made more effective if designed to take advantage of
these effects.
Does Motivation Contribute on Health Care Provision?
Authors: Landa Elizabeth
Published: May 2018

This study aimed to examine the contribution of employee motivation on provision of customer care in public health centres, in Morogoro Municipality. Data were collected from four selected public health institutions namely Morogoro General Hospital, Nunge Health Centre, Mafiga Health Centre and Kingolwila Health Centre respectively. The sample of 124 respondents were used, that is; employees and heads of the health centres. Collected data were coded using SPSS, where frequencies, percentages and chi-square were employed. The study identified that career development, training, appreciation, recognition, membership to the Social Security Fund, team work, working condition, paid leave, housing allowances and acting allowance were, the motivation schemes provided to public health employees. However public health workers are motivated by being a member on social security fund, medical cover, supervision, and job security. The result shows that there is significant difference between the employee who are motivated and those who are not motivated with regard to their provision of customer care to patients. The study concludes that most of the employees are not motivated by the existing motivation schemes which consequences lower their ability to provide the appropriate health services. The study recommends that strategies for improving motivation of employee to improve customer care include increase salary, improve working condition, pay housing allowance to all employees, allowance such as leave, overtime should be paid on time, promotion should be made in appropriate time and fair.
A Case of Parasitic Twinning or Caudal Duplication in a Dog
Authors: Grimes Janet A. , Hespel Adrien-Maxence , Cole Robert C. , Dillon A. Ray
Published: May 2018

A 6 mo old 13.5 kg (29.7 lb) male intact American Staffordshire terrier was evaluated for a history of supernumerary pelvic limbs, with malodorous discharge from a supernumerary penis. Imaging (radiographs, abdominal ultrasound, and computed tomography with excretory urogram) showed a supernumerary pelvis with associated pelvic limbs, no osseous continuity with the primary spinal column, a colonic diverticulum extending to the supernumerary pelvis, an enlarged left kidney with a ureter connecting to a single bladder, right renal aplasia, a single descended testicle in the primary scrotum, an intra-abdominal cryptorchid testicle, and two unidentifiable soft tissue masses. At surgery, a single ileum was present with a primary and accessory cecum and colon and the accessory colon entering the supernumerary pelvis. The accessory cecum and colon, right kidney, two unknown soft tissue masses, and the single descended testicle were removed. The right kidney had a ureter that anastomosed with the accessory colon at its entry into the supernumerary pelvis. The supernumerary pelvis and hind limbs were not removed. Five months after surgery, the dog was reported to be doing well clinically. Caudal duplication is extremely rare in veterinary medicine. The appearance of supernumerary external structures may indicate internal connections as well.
Bicipital Tendinopathy and Carpal Valgus Following a Distant Direct Thoracoabdominal Skin Flap in a German Shepherd with Necrotizing Fasciitis
Authors: Mielke Benjamin , Kulendra Nicola , Halfacree Zoe , Kulendra Elvin
Published: May 2018

A 4 mo old German shepherd dog was presented following an acute onset lameness and swelling of the thoracic limb. Clinical signs, surgical findings, and culture results were consistent with a diagnosis of necrotizing fasciitis. Initial management consisted of extensive surgical debridement, wound lavage, and bandaging. Surgical closure was achieved with an axillary fold flap and distant direct single-pedicle thoracoabdominal flap. Three mo later, following deterioration of the lameness that was associated with carpal valgus, carpal subluxation, and tendinopathy of the distal radial insertion of the biceps brachii tendon, a closing wedge pancarpal arthrodesis and tenotomy of the biceps brachii tendon was performed. We hypothesize that extensive soft tissue trauma and subsequent fibrosis and tendon contracture following soft tissue reconstruction contributed to the complications seen. To the authors’ knowledge, this is the first report of carpal valgus deformity and biceps brachii tendinopathy following a distant direct skin flap and axillary skin fold flap.
A Pivotal Field Study to Support the Registration of Levothyroxine Sodium Tablets for Canine Hypothyroidism
Authors: Lewis Victoria A. , Morrow Carla M.K. , Jacobsen Johnny A. , Lloyd W. Eugene
Published: May 2018

A prospective, pivotal, multicenter field study to evaluate the dose regimen, effectiveness, and safety of levothyroxine sodium tablets, USP for the treatment of hypothyroidism and hypothyroidism-associated clinical signs in dogs was conducted. Ninety-two dogs diagnosed with primary hypothyroidism met the entrance criteria and were enrolled into the study. Levothyroxine sodium was administered to each dog on a daily basis either as the whole dose q 24 hr or as half the dose q 12 hr. Dosing started at 0.1 mg/10 lb (0.022 mg/kg) and continued for approximately 6 mo to Day 182. During this time, the thyroid status of each dog was evaluated at monthly intervals. For the determination of effectiveness, dogs classified as euthyroid at Day 182, based on their thyroid hormone values, were considered treatment successes. Results of the statistical analysis showed that there was no difference between the two dosing regimens (P = .11) and that when the data from both groups were pooled, the overall success rate was 75.64% (95% confidence interval = 66.34%). By Day 182, improvement and/or resolution of hypothyroidism-associated clinical signs was observed in all categories. No abnormal trends in the reported adverse events were observed.
Eclosión de huevos de artemia (Artemia franciscana Kellogg) a nivel de laboratorio en la Universidad Nacional Agraria, Managua, Nicaragua
Authors: Reyes Flores Francisco , Reyes Rosa María , Salgado Heraldo , Cornejo Harvin
Published: May 2018

En el estudio de eclosión de Artemia franciscana a nivel de laboratorio, tuvo como objetivo determinar el tipo de tratamiento que se adapta a condiciones de laboratorio brindando buenos resultados para la eclosión del crustáceo Artemia (Artemia franciscana Kellogg). La metodología utilizada consistió en la toma de datos en el laboratorio evaluando los siguientes tratamientos: Toma de pH; Toma de temperatura; Salinidad y Medición de Sobrevivencia. Una vez establecido el ensayo se procedió a colocar los huevo de Artemia, dejándolos por un periodo de 48 horas para iniciar el proceso eclosivo del crustáceo. El manejo que se aplicó en el estudio consistió en tomar datos de temperatura y del pH para llevar un control y seguimiento a la eclosión de Artemia; así como el control de la alimentación a base de una dieta de pastilla de alga Spirulina máxima triturada. De acuerdo al análisis estadístico realizado con metodología de DUNCAN, correlación de Pearson y procesado en el programa estadístico INFOSTAT indican que la mejor eclosión se registró en el tratamiento D con un 65.40 % dando pautas de ser el tratamiento que mejor se adaptó a las condiciones de laboratorio. La sobrevivencia de los otros tratamientos es positiva y adaptable a condiciones de laboratorio donde es recomendable utilizar recipientes con mayor capacidad de almacenamiento de agua. Recomendándose para futuros cultivos de Artemia llevar a cabo el manejo ya implementado en el Laboratorio de Ciencias Biológicas de la Universidad Nacional Agraria para un mayor rendimiento en la sobrevivencia del estudio y seguir proporcionando información para la eclosión de dicho crustáceo que representa una opción alimenticia de bajo impacto a productores pesqueros del país.
Actividad repelente e insecticida de hojas, flores y extractos de llama del bosque (Spathodea campanulata B.), en gorgojos de granos almacenados (Sitophilus zeamais M.)
Authors: Alarcón Reynaldo , Guzmán Thomas , Penieres José , Navarrete Rosa
Published: May 2018

El gorgojo del maíz (Sitophilus zeamais Motschulsky. Coleóptera: Curculionidae), es una de las principales plagas del grano en “post cosecha”. Las pérdidas anuales de post cosecha de cultivos de cereales son el resultado de daños de insectos, degradación microbiana y otros factores, se estima de 10 al 25 % de pérdida de producción a nivel mundial. Tradicionalmente estas plagas se controlan con insecticidas químicos que si no se manejan adecuadamente, ocasionan problemas de contaminación ambiental y residuos en alimentos. Como una alternativa está el uso de insecticidas naturales que son menos tóxicos y pueden ser elaborados por los agricultores. Entre los insecticidas naturales están los compuestos derivados de nicotina, piretrinas naturales, neem (Azaradichtina) y las hojas, flores y extractos del árbol llama del bosque, que pueden constituir una alternativa para el control de plagas en granos almacenados como el gorgojo del maíz. En esta investigación se realizaron ensayos para determinar la actividad repelente e insecticida de hojas y flores de llama del bosque, así como de los extractos respectivos, en una cámara con túnel de viento del laboratorio de ecología química de insectos de ECOSUR, Tapachula, Chiapas, México. Con base en los resultados obtenidos se determinó efecto repelente de flores y hojas sobre gorgojos del maíz en concentración de 2 g/200 g de maíz a las 2 y 17 horas de aplicación. La mayor actividad insecticida se presentó a las 12 horas de la aplicación de extractos y el mejor efecto insecticida fue con el extracto de flores en concentraciones de 2.0 y 1.5 mg/ml.
Nuestra vulnerabilidad ante «choques» puede y debe ser reducida
Authors: Lazo Carmen Aída
Published: May 2018

Revista ciencia, cultura y sociedad Vol. 4 No. 1 enero-junio 2017; 49-52