bluuebunny/crossref_metadata_2025 huggingface dataset:
Ship-borne aerosol profiling with lidar over the Atlantic Ocean: from pure marine conditions to complex dust–smoke mixtures
Authors: Bohlmann Stephanie , Baars Holger , Radenz Martin , Engelmann Ronny , Macke Andreas
Published: July 2018

Abstract. The multi-wavelength Raman lidar PollyXT has been
regularly operated aboard the research vessel Polarstern on
expeditions across the Atlantic Ocean from north to south and vice versa. The
lidar measurements of the RV Polarstern cruises PS95 from
Bremerhaven, Germany, to Cape Town, Republic of South Africa (November 2015),
and PS98 from Punta Arenas, Chile, to Bremerhaven, Germany (April/May 2016),
are presented and analysed in detail. The latest set-up of
PollyXT allows improved coverage of the marine boundary
layer (MBL) due to an additional near-range receiver. Three case studies provide an overview of the aerosol detected over the
Atlantic Ocean. In the first case, marine conditions were observed near South
Africa on the autumn cruise PS95. Values of optical properties
(depolarisation ratios close to zero, lidar ratios of 23 sr at 355 and
532 nm) within the MBL indicate pure marine aerosol. A layer of dried marine
aerosol, indicated by an increase of the particle depolarisation ratio to
about 10 % at 355 nm (9 % at 532 nm) and thus confirming the
non-sphericity of these particles, could be detected on top of the MBL. On
the same cruise, an almost pure Saharan dust plume was observed near the
Canary Islands, presented in the second case. The third case deals with
several layers of Saharan dust partly mixed with biomass-burning smoke
measured on PS98 near the Cabo Verde islands. While the MBL was partly mixed
with dust in the pure Saharan dust case, an almost marine MBL was observed in
the third case. A statistical analysis showed latitudinal differences in the optical
properties within the MBL, caused by the down-mixing of dust in the tropics
and anthropogenic influences in the northern latitudes, whereas the optical
properties of the MBL in the Southern Hemisphere correlate with typical
marine values. The particle depolarisation ratio of dried marine layers
ranged between 4 and 9 % at 532 nm. Night measurements from PS95 and PS98 were used to illustrate the potential
of aerosol classification using lidar ratio, particle depolarisation ratio at
355 and 532 nm, and Ångström exponent. Lidar ratio and particle
depolarisation ratio have been found to be the main indicator for particle
type, whereas the Ångström exponent is rather variable.
Investigating the Impact of Aerosol Deposition on Snow
Melt over the Greenland Ice Sheet Using a Large-Ensemble
Kernel
Authors: Li Yang , Flanner Mark G.
Published: July 2018

Abstract. Accelerating surface melt on the Greenland Ice Sheet (GrIS) has led to a doubling of Greenland's contribution to global sea level rise during recent decades. Black carbon (BC), dust, and other light absorbing impurities (LAI) darken the surface and enhance snow melt by boosting the absorption of solar energy. It is therefore important for coupled aerosol-climate and ice sheet models to include snow darkening effects from LAI, and yet most do not. In this study, we conduct several thousand simulations with the Community Land Model (CLM) component of the Community Earth System Model (CESM) to characterize changes in melt runoff due to variations in the amount, timing, and nature (wet or dry) of BC deposition on the GrIS. From this large matrix of simulations, we develop a kernel relating runoff to the location, month, year (from 2006–2015), and magnitudes of BC concentration within precipitation and dry deposition flux. BC deposition during June–August causes the largest increase in annually-integrated runoff, but winter deposition events also exert large (roughly half as great) runoff perturbations due to re-exposure of impurities at the snow surface during summer melt. Current BC deposition fluxes simulated with the atmosphere component of CESM induce a climatological-mean increase in GrIS-wide runoff of ~ 8 Gt/yr, or + 6.8 % relative to a paired simulation without BC deposition. We also provide linear equations that relate the increase in total runoff to GrIS-wide wet and dry BC deposition fluxes. It is our hope that the runoff kernel and simple equations provided here can be used to extend the utility of state-of-the-art aerosol models.
Methane at Svalbard and over the European Arctic Ocean
Authors: Platt Stephen M. , Eckhardt Sabine , Ferré Benedicte , Fisher Rebecca E. , Hermansen Ove , Jansson Pär , Lowry David , Nisbet Euan G. , Pisso Ignacio , Schmidbauer Norbert , Silyakova Anna , Stohl Andreas , Svendby Tove M. , Vadakkepuliyambatta Sunil , Mienert Jürgen , Lund Myhre Cathrine
Published: July 2018

Abstract. Methane (CH4) is a powerful greenhouse gas and atmospheric mixing ratios have been increasing since 2005. Therefore, quantification of CH4 sources is essential for effective climate change mitigation. Here we report observations of the CH4 mixing ratios measured at Zeppelin Observatory (Svalbard) in the Arctic and aboard the Research Vessel (RV) Helmer Hanssen over the Arctic Ocean from June 2014 to December 2016, as well as the long-term CH4 trend measured at the Zeppelin Observatory (Svalbard) from 2001–2017. We investigated areas over the European Arctic Ocean to identify possible hot spot regions emitting CH4 from the ocean to the atmosphere, and used state-of-the-art modelling (FLEXPART) combined with updated emissions inventories to identify CH4 sources. Furthermore, we collected air samples in the region as well as samples of gas hydrates, obtained from the sea floor using a new technique developed as part of this work. Using this new methodology, we evaluated the suitability of ethane and isotopic signatures (δ13C in CH4) as tracers for ocean-to-atmosphere CH4 emission. We show that the mean atmospheric CH4 mixing ratio in the Arctic increased by 5.9 ± 0.38 parts per billion by volume (ppb) per year (yr−1) from 2001–2017. Meanwhile most large excursions from the baseline CH4 mixing ratio over the European Arctic Ocean are due to long-range transport from land-based sources, lending confidence to the present inventories for high latitude CH4 emissions. However, we also identify a potential hot spot region with ocean-atmosphere CH4 flux North of Svalbard (80.4° N, 12.8° E) of up to 26 nmol m−2 s−1 from a large mixing ratio increase at the location of 30 ppb. Since this flux is highly consistent with previous constraints (both spatially and temporally), there is no evidence that the area of interest North of Svalbard is unique in the context of the wider Arctic. Rather, that the meteorology at the time of the observation was unique in the context of the measurement time series, i.e. we obtained, over the short course of the episode, measurements highly sensitive to emissions over an active seep site, without sensitivity to land based emissions.
A study of long-range transported smoke aerosols in the Upper Troposphere/Lower Stratosphere
Authors: Hu Qiaoyun , Goloub Philippe , Veselovskii Igor , Bravo-Aranda Juan-Antonio , Popovici Ioana , Podvin Thierry , Haeffelin Martial , Lopatin Anton , Pietras Christophe , Huang Xin , Torres Benjamin , Chen Cheng
Published: July 2018

Abstract. Long-range transported smoke aerosols in the UTLS (Upper Troposphere/Lower Stratosphere) over Europe were detected in Summer 2017. The measurements of ground-based instruments and satellite sensors indicate that the UTLS aerosol layers were originated from Canadian wildfires and were transported to Europe by UTLS advection. In this study, the observations of two multi-wavelength Raman Lidar systems in northern France (Lille and Palaiseau) are used to derive aerosol properties, such as optical depth of the UTLS layer, Lidar ratios at 355 and 532 nm and particle linear depolarization ratios at 355, 532 and 1064 nm. The optical depth of the UTLS layers at 532 nm varies from 0.05 to above 0.20, with very weak spectral dependence between 355 and 532 nm. Lidar ratios at 355 nm are in 31 ± 15 sr to 45 ± 9 sr range and at 532 nm, the Lidar ratios are in the range of 54 ± 12 sr to 58 ± 9 sr. Such spectral dependence of Lidar ratio is known to be a characteristic feature of aged smoke. The typical particle depolarization ratios in the UTLS smoke layer are 25 ± 4 % at 355 nm, 19 ± 3 % at 532 nm and 4.5 ± 0.8 % at 1064 nm. The relatively high depolarization ratios and such spectral dependence are an indication of a complicated morphology of aged smoke particles. We found an increase of depolarization ratio versus transport time. The depolarization ratio at 532 nm increases from below 2–5 % for fresh smoke to over 20 % for smoke aged more than 20 days. The 3β + 2α observations of two cases at Palaiseau and Lille sites were inverted to the aerosol microphysical properties using regularization algorithm. The particles distribute in the 0.1–1.0 μm range with effective radius of 0.33 ± 0.10 μm for both cases. The derived complex refractive indices are 1.52 (± 0.05) + i0.021 (± 0.010) and 1.55 (± 0.05) + i0.028 (± 0.014) for Palaiseau and Lille data. The retrieved aerosol properties were used to calculate the direct radiative forcing (DRF) effect specific to the UTLS aerosol layers. The simulations derive daily net DRF efficiency of −79.6 W m−2 τ−1 at the bottom of the atmosphere for Lille observations. At the top of the atmosphere, the net DRF efficiency is −7.9 W m−2 τ−1. The results indicate that the UTLS aerosols strongly reduce the radiation reaching the terrestrial surface by absorption. The heating rate of the UTLS layers is estimated to be 3.7 K day−1. The inversion of Palaiseau data leads to similar results. The heating rate predicts a temperature increase within the UTLS aerosol layer, which has been observed by the radiosonde temperature measurements.
Remote sensing of aerosols with small satellites in formation flight
Authors: Knobelspiesse Kirk , Nag Sreeja
Published: July 2018

Abstract. Determination of aerosol optical properties with orbital passive remote
sensing is a difficult task, as observations often have limited information.
Multi-angle instruments, such as the Multi-angle Imaging SpectroRadiometer
(MISR) and the POlarization and Directionality of the Earth's Reflectances
(POLDER), seek to address this by making information-rich multi-angle
observations that can be used to better retrieve aerosol optical
properties. The paradigm for such instruments is that each angle view is made
from one platform, with, for example, a gimballed sensor or multiple fixed
view angle sensors. This restricts the observing geometry to a plane within
the scene bidirectional reflectance distribution function (BRDF) observed at
the top of the atmosphere (TOA). New technological developments, however,
support sensors on small satellites flying in formation, which could be a
beneficial alternative. Such sensors may have only one viewing direction
each, but the agility of small satellites allows one to control this
direction and change it over time. When such agile satellites are flown in
formation and their sensors pointed to the same location at approximately the
same time, they could sample a distributed set of geometries within the scene
BRDF. In other words, observations from multiple satellites can take a
variety of view zenith and azimuth angles and are not restricted to one
azimuth plane as is the case with a single multi-angle instrument. It is not
known, however, whether this is as potentially capable as a multi-angle platform
for the purposes of aerosol remote sensing. Using a systems engineering tool
coupled with an information content analysis technique, we investigate the
feasibility of such an approach for the remote sensing of aerosols. These
tools test the mean results of all geometries encountered in an orbit. We
find that small satellites in formation are equally capable as multi-angle
platforms for aerosol remote sensing, as long as their calibration accuracies
and measurement uncertainties are equivalent. As long as the viewing
geometries are dispersed throughout the BRDF, it appears the quantity of view
angles determines the information content of the observations, not the
specific observation geometry. Given the smoothly varying nature of BRDF's
observed at the TOA, this is reasonable and supports the viability of
aerosol remote sensing with small satellites flying in formation. The
incremental improvement in information content that we found with number of
view angles also supports the concept of a resilient mission comprised of
multiple satellites that are continuously replaced as they age or fail.
Laser induced fluorescence based detection of atmospheric nitrogen dioxide and comparison of different techniques during the PARADE 2011 field campaign
Authors: Javed Umar , Kubistin Dagmar , Martinez Monica , Pollmann Jan , Rudolf Markus , Parchatka Uwe , Reiffs Andreas , Thieser Jim , Schuster Gerhard , Horbanski Martin , Pöhler Denis , Crowley John N. , Fischer Horst , Lelieveld Jos , Harder Hartwig
Published: July 2018

Abstract. GANDALF (Gas Analyzer for Nitrogen Dioxide Applying Laser-induced Fluorescence), a new instrument for the detection of nitrogen dioxide based on the laser-induced fluorescence (LIF) technique, is presented in this paper. GANDALF is designed for ground based and air-borne deployment with a robust calibration system. In the current setup, it uses a multi-mode diode laser (447–450 nm) and performs in situ, continuous, and autonomous measurements with a laser pulse repetition rate of 5 MHz. The performance of GANDALF was tested during the field experiment at a forested location with urban influence where NOx levels were between 0.12 and 22 parts per billion by volume (ppbv). Based on the field results, the limit of detection is estimated at 5–10 parts per trillion by volume (pptv) in 60 s at a signal to noise ratio (SNR) of 2. The overall accuracy and precision of the instrument are better than 5 % (1 σ) and 0.5 % + 3 pptv (1 σ min−1), respectively. A comparison of nitrogen dioxide measurements based on several techniques during the field campaign is presented to explore methodic differences.
Electromagnetic field observations by the DEMETER satellite in connection with the 2009 L’Aquila earthquake
Authors: Bertello Igor , Piersanti Mirko , Candidi Maurizio , Diego Piero , Ubertini Pietro
Published: July 2018

Abstract. To define a background in the electromagnetic emissions above seismic regions, it is necessary to define the statistical distribution of the wave energy in absence of seismic activity and any other anomalous input (e.g. solar forcing). This paper presents a completely new method to determine both the environmental and instrumental background applied to the entire DEMETER satellite electric and magnetic field data over L’Aquila. Our technique is based on a new data analysis tool called ALIF (Adaptive Local Iterative Filtering, [Cicone et al., 2016 and 2017; Piersanti et al., 2017]). To evaluate the instrumental noise, we performed a multiscale statistical analysis, in which the instantaneous relative energy (ϵrel), kurtosis and Shannon entropy was calculated. To estimate the environmental noise, a background map, divided into 1° × 1° latitude/longitude cells, of the averaged relative energy (ϵrel) has been constructed, taking into account the geomagnetic activity conditions, the presence of seismic activity and the local time sector of the satellite orbit. Any distinct signal different (over a certain threshold) from both the instrumental and environmental backgrounds will be considered as a case event to be investigated. Interestingly, on April 4, 2009, when DEMETER flew exactly over L’Aquila at UT = 20:29, an anomalous signal was observed at 333 Hz on both the electric and magnetic field data, whose characteristics seem to be related to pre-seismic activity.
Intermediate water flows in the western South Pacific: as revealed by individual Argo floats trajectories and a model re-analysis
Authors: Barbot Simon , Petrenko Anne , Maes Christophe
Published: July 2018

Abstract. Thanks to the autonomous Argo floats of the OUTPACE cruise (Oligotrophy to UlTra-oligotrophy PACific Experiment) and of the THOT
(TaHitian Ocean Time series) project, some features of intermediate-flow dynamics, at around 1000 m depth,
within the central and western South Pacific Ocean (around 19∘ S,
156∘ E–150∘ W) are described. In the Coral Sea, we highlight minima in dissolved
oxygen of 140 µmol kg−1 that are associated with the signature of a
southward transport of waters between two zonal jets: from the North Vanuatu
Jet to the North Caledonia Jet. This transport takes place in the core of a
cyclonic eddy or via the path between a cyclonic eddy and an anticyclonic
one, highlighting the importance of mesoscale dynamics in upper thermocline
and surface layers. Further east, we observe a strong meridional velocity
shear with long-term float trajectories going either eastward or westward in
the lower thermocline. More interestingly, these trajectories also exhibit
some oscillatory features. Those trajectories can be explained by a single
Rossby wave of 160-day duration and 855 km wavelength. Considering the
thermohaline context, we confirm the meridional shear of zonal velocity and
highlight a permanent density front that corresponds to the interface between
Antarctic intermediate waters and North Pacific deep waters. Hence both
circulation and thermohaline contexts are highly prone to instabilities
and wave propagation.
Abyssal plain faunal carbon flows remain depressed 26 years after a simulated deep-sea mining disturbance
Authors: Stratmann Tanja , Lins Lidia , Purser Autun , Marcon Yann , Rodrigues Clara F. , Ravara Ascensão , Cunha Marina R. , Simon-Lledó Erik , Jones Daniel O. B. , Sweetman Andrew K. , Köser Kevin , van Oevelen Dick
Published: July 2018

Abstract. Future deep-sea mining for polymetallic nodules in abyssal plains will
negatively impact the benthic ecosystem, but it is largely unclear whether
this ecosystem will be able to recover from mining disturbance and if so, to
what extent and at what timescale. During the “DISturbance and
reCOLonization” (DISCOL) experiment, a total of 22 % of the seafloor
within a 10.8 km2 circular area of the nodule-rich seafloor in the Peru
Basin (SE Pacific) was ploughed in 1989 to bury nodules and mix the surface
sediment. This area was revisited 0.1, 0.5, 3, 7, and 26 years after the
disturbance to assess macrofauna, invertebrate megafauna and fish density and
diversity. We used this unique abyssal faunal time series to develop
carbon-based food web models for each point in the time series using the
linear inverse modeling approach for sediments subjected to two disturbance
levels: (1) outside the plough tracks; not directly disturbed by plough, but
probably suffered from additional sedimentation; and (2) inside the plough
tracks. Total faunal carbon stock was always higher outside plough tracks
compared with inside plough tracks. After 26 years, the carbon stock inside
the plough tracks was 54 % of the carbon stock outside plough tracks.
Deposit feeders were least affected by the disturbance, with modeled
respiration, external predation, and excretion rates being reduced by only
2.6 % inside plough tracks compared with outside plough tracks after
26 years. In contrast, the respiration rate of filter and suspension feeders
was 79.5 % lower in the plough tracks after 26 years. The “total system
throughput” (T..), i.e., the total sum of modeled carbon flows in the food web,
was higher throughout the time series outside plough tracks compared with
the corresponding inside plough tracks area and was lowest inside plough tracks
directly after the disturbance (8.63 × 10−3 ± 1.58 × 10−5 mmol C m−2 d−1). Even 26 years after the DISCOL
disturbance, the discrepancy of T.. between outside and inside plough
tracks was still 56 %. Hence, C cycling within the faunal compartments of
an abyssal plain ecosystem remains reduced 26 years after physical
disturbance, and a longer period is required for the system to recover from
such a small-scale sediment disturbance experiment.
Short Communication: Increasing vertical attenuation length of
cosmogenic nuclide production on steep slopes negates topographic shielding corrections for catchment erosion rates
Authors: DiBiase Roman A.
Published: July 2018

Abstract. Interpreting catchment-mean erosion rate from in situ produced cosmogenic 10Be concentration in stream sands requires calculating the catchment-mean 10Be surface production rate and effective mass attenuation length, both of which can vary locally due to topographic shielding and slope effects. The most common method for calculating topographic shielding accounts only for the effect of shielding at the surface, leading to catchment-mean corrections of up to 20 % in steep landscapes, and makes the simplifying assumption that the effective mass attenuation length for a given nuclide production mechanism is spatially uniform. Here I evaluate the validity of this assumption using a simplified catchment geometry to calculate the spatial variation in surface skyline shielding, effective mass attenuation length, and the total effective shielding factor for catchments with mean slopes ranging from 0° to 80°. For flat catchments (i.e., uniform elevation of bounding ridgelines), the increase in effective attenuation length as a function of hillslope angle and skyline shielding leads to a catchment-mean total effective shielding factor of one, implying that no topographic shielding factor is needed when calculating catchment-mean vertical erosion rates. For dipping catchments (as characterized by a plane fit to the bounding ridgelines), the catchment-mean total effective shielding factor is also one, except for cases of extremely steep range-front catchments, where the shielding correction is counterintuitively greater than one. These results indicate that in most cases, topographic shielding corrections are inappropriate for calculating catchment-mean erosion rates, and only needed for steep catchments with non-uniform distribution of quartz and/or erosion rate. By accounting only for shielding of surface production, existing shielding approaches introduce a slope-dependent systematic error that could lead to spurious interpretations of relationships between topography and erosion rate.
Simulation Improvements of ECHAM5-NEMO3.6 and ECHAM6-NEMO3.6 Coupled Models Compared to MPI-ESM and the Corresponding Physical Mechanisms
Authors: Gui Shu , Yang Ruowen , Cao Jie
Published: July 2018

Abstract. To improve the model simulation through decisive coupling mechanisms, rather than blindly updating the parameterization schemes, it is necessary to compare model performances between the CGCMs with the same atmospheric or oceanic component model. Therefore, two new CGCMs have been developed with the same oceanic component model, namely ECHAM5-NEMO3.6 and ECHAM6-NEMO3.6. The MPI-ESM that consists of ECHAM6 and MPIOM has also been employed. Experiments are carried out with the same settings in coupler and individual component model if applicable, and the new models show substantial improvements in the simulation of SST, precipitation and ocean currents. Further analysis has made it clear that the primary cause of SST biases in ECHAM5-NEMO3.6 and ECHAM6-NEMO3.6 can be attributed to the momentum field, while oceanic dynamics and surface radiation budget are accountable for more SST deviations in the MPI-ESM. Inter-model comparison between the coupled models with the same oceanic model suggests that cumulus convection is in the central part of simulation differences, which finally influence the SST through WES feedback mechanism. Whereas the OGCM replacement shows that latent heat of evaporation plays a predominant role in changing SST and surface radiation budget, and eventually bringing about variations in air temperature and atmospheric circulation. The mechanisms revealed in this study provide a new perspective of bias genesis during model coupling, which can be helpful for tuning other climate models towards a more realistic simulation.
Understanding model biases in the diurnal cycle of evapotranspiration: a case study in Luxembourg
Authors: Renner Maik , Brenner Claire , Mallick Kaniska , Wizemann Hans-Dieter , Conte Luigi , Trebs Ivonne , Wei Jianhui , Wulfmeyer Volker , Schulz Karsten , Kleidon Axel
Published: July 2018

Abstract. The diurnal forcing of solar radiation is the largest signal within the Earth system and dominates the diurnal cycle of the turbulent heat fluxes and evapotranspiration (λE) over land. Incoming solar radiation (Rsd) also shapes temperature, vapor pressure deficit and wind speed known as important controls on λE. Current process-based λE schemes used in remote sensing and land–surface modeling differ in how these controls on λE are represented and which input variables are required. Here, we analyze how well different surface energy balance schemes are able to reproduce the diurnal cycle and how the diurnal signals of observed input variables actually influence the resulting diurnal pattern of λE. As additional constraint for model evaluation we estimate a linear and a non-linear phase shift component of a surface variable (e.g. λE) to incoming solar radiation. We illustrate our analysis with observations from an eddy covariance station at a temperate grassland site in Luxembourg with a focus on clear sky conditions. During the field campaign in 2015 a summer drought led to a dry-down of soil moisture which allows for studying the effect of wet and dry conditions on the diurnal cycle. We found a remarkable, almost linear relationship of λE with Rsd, which exhibits a significant positive phase lag during wet periods. This phase lag in λE was compensated by a preceding phase lag of the sensible heat flux. Vapor pressure deficit (Da, often used as input for Penman–Monteith based approaches) exhibits a strong phase lag, which is driven by air temperature reflecting large diurnal heat storage changes in the lower atmosphere. This large phase lag in Da, which is not seen in λE, explains why actual and potential evapotranspiration approaches can show systematic deviations from observations at the sub-daily time scale and highlight the need for a time-dependent non-linear compensation through the conductance parameterization. The surface to air temperature gradient used as input in energy balance residual approaches corresponds rather well with its linear response and phase lag to the observed sensible heat flux under both, wet and dry conditions. This simplifies the conductance parameterization and explains the better correlation of these models at the sub-daily time scale. We conclude that the analysis of phase lags at the sub-daily time-scale provides valuable information on the drivers of the surface–atmosphere exchange, which can be used to evaluate and improve the representation of land–atmosphere coupling in land–surface schemes.
Intensity–duration–frequency (IDF) rainfall curves in Senegal
Authors: Sane Youssouph , Panthou Geremy , Bodian Ansoumana , Vischel Theo , Lebel Thierry , Dacosta Honore , Quantin Guillaume , Wilcox Catherine , Ndiaye Ousmane , Diongue-Niang Aida , Diop Kane Mariane
Published: July 2018

Abstract. Urbanization resulting from sharply increasing demographic pressure and
infrastructure development has made the populations of many tropical areas
more vulnerable to extreme rainfall hazards. Characterizing extreme rainfall
distribution in a coherent way in space and time is thus becoming an
overarching need that requires using appropriate models of
intensity–duration–frequency (IDF) curves. Using a 14 series of 5 min
rainfall records collected in Senegal, a comparison of two generalized
extreme value (GEV) and scaling models is carried out, resulting in the
selection of the more parsimonious one (four parameters), as the recommended model for
use. A bootstrap approach is proposed to compute the uncertainty associated
with the estimation of these four parameters and of the related rainfall
return levels for durations ranging from 1 to 24 h. This study
confirms previous works showing that simple scaling holds for characterizing
the temporal scaling of extreme rainfall in tropical regions such as
sub-Saharan Africa. It further provides confidence intervals for the
parameter estimates and shows that the uncertainty linked to the estimation
of the GEV parameters is 3 to 4 times larger than the uncertainty linked to
the inference of the scaling parameter. From this model, maps of IDF
parameters over Senegal are produced, providing a spatial vision of their
organization over the country, with a north to south gradient for the
location and scale parameters of the GEV. An influence of the distance from
the ocean was found for the scaling parameter. It is acknowledged in
conclusion that climate change renders the inference of IDF curves sensitive
to increasing non-stationarity effects, which requires warning end-users that
such tools should be used with care and discernment.
Parameterization of the spectral light absorption coefficient of phytoplankton in the Baltic Sea: general, monthly and two-component variants of approximation formulas
Authors: Meler Justyna , Woźniak Sławomir B. , Stoń-Egiert Joanna , Woźniak Bogdan
Published: July 2018

Abstract. The paper presents approximate formulas for parameterizing the coefficient of light absorption by phytoplankton aph(λ) in Baltic Sea surface waters. Over a thousand absorption spectra (in the 350–750 nm range), recorded during nine years of research carried out in different months of the year and in various regions of the southern and central Baltic, were used to derive these parameterizations. The analysed empirical material was characterized by a wide range of variability: the total chlorophyll a concentration (Tchla) varied between 0.3 and > 140 mg m−3, the ratio of the sum of all accessory pigment concentrations to chlorophyll a (ΣCi / Tchla) varied between 0.21 and 1.5, and the absorption coefficients aph(λ) at individual light wavelengths varied over almost three orders of magnitude. Different versions of the parameterization formulas were derived on the basis of the data gathered: a one-component parameterization in the classic form of a power function with Tchla as the only variable, and a two-component formula – the product of the power and exponential functions, with Tchla and ΣCi / Tchla as variables. There were distinct differences between the general version of the one-component parameterization and its variants developed for individual months of the year. In contrast to the general parameterization, both the monthly and the two-component variants enable, at least partially, the variability of pigment composition occurring throughout the year in the Baltic phytoplankton populations examined here to be taken into account.
Glacio-hydrological melt and run-off modelling: application of a limits of acceptability framework for model comparison and selection
Authors: Mackay Jonathan D. , Barrand Nicholas E. , Hannah David M. , Krause Stefan , Jackson Christopher R. , Everest Jez , Aðalgeirsdóttir Guðfinna
Published: July 2018

Abstract. Glacio-hydrological
models (GHMs) allow us to develop an understanding of how future climate
change will affect river flow regimes in glaciated watersheds. A variety of
simplified GHM structures and parameterisations exist, yet the performance of
these are rarely quantified at the process level or with metrics beyond
global summary statistics. A fuller understanding of the deficiencies in
competing model structures and parameterisations and the ability of models to
simulate physical processes require performance metrics utilising the full
range of uncertainty information within input observations. Here, the
glacio-hydrological characteristics of the Virkisá River basin in
southern Iceland are characterised using 33 signatures derived from
observations of ice melt, snow coverage and river discharge. The uncertainty
of each set of observations is harnessed to define the limits of
acceptability (LOA), a set of criteria used to objectively evaluate the
acceptability of different GHM structures and parameterisations. This
framework is used to compare and diagnose deficiencies in three melt and
three run-off-routing model structures. Increased model complexity is shown to
improve acceptability when evaluated against specific signatures but does
not always result in better consistency across all signatures, emphasising
the difficulty in appropriate model selection and the need for multi-model
prediction approaches to account for model selection uncertainty. Melt and
run-off-routing structures demonstrate a hierarchy of influence on river
discharge signatures with melt model structure having the most influence on
discharge hydrograph seasonality and run-off-routing structure on
shorter-timescale discharge events. None of the tested GHM structural
configurations returned acceptable simulations across the full population of
signatures. The framework outlined here provides a comprehensive and rigorous
assessment tool for evaluating the acceptability of different GHM process
hypotheses. Future melt and run-off model forecasts should seek to diagnose
structural model deficiencies and evaluate diagnostic signatures of system
behaviour using a LOA framework.
Advanced CFD-MBS coupling to assess low-frequency emissions
from wind turbines
Authors: Klein Levin , Gude Jonas , Wenz Florian , Lutz Thorsten , Krämer Ewald
Published: July 2018

Abstract. The low-frequency emissions from a generic 5 MW turbine are investigated numerically. In order to regard airborne noise and structure-borne noise simultaneously a process chain was developed. It considers fluid-structure coupling (FSC) of a computational fluid dynamics (CFD) solver and multibody simulations (MBS) solver as well as a Ffowcs Williams-Hawkings (FW-H) acoustic solver. The approach was applied to a generic 5 MW turbine to get more insight into the sources and mechanisms of low-frequency emissions from wind turbines. For this purpose simulations with increasing complexity in terms of considered components in the CFD model, degrees of freedom in the structural model and inflow in the CFD model were conducted. Consistent with literature, it has been found that aeroacoustic low-frequency emission is dominated by the blade-passing frequency harmonics. The tower base loads, which excite seismic emission, tend to be dominated by structural eigenfrequencies with increasing complexity of the model. The main source of aeroacoustic emissions is the blade-tower interaction and the contribution of the tower as an acoustic emitter is stronger than the contribution of the rotor. Aerodynamic tower loads also significantly contribute to the external excitation acting on the structure of the wind turbine.
Simulation of transient gusts on the NREL 5 MW wind turbine using the URANS solver THETA
Authors: Länger-Möller Annika
Published: July 2018

Abstract. A procedure to propagate longitudinal transient gusts through a flow
field by using the resolved-gust approach is implemented in the URANS solver
THETA. Both the gust strike of a 1−cos⁡() gust and an extreme operating
gust following the IEC 61400-1 standard are investigated on the generic NREL
5 MW wind turbine at rated operating conditions. The impact of both gusts on
pressure distributions, rotor thrust, rotor torque, and flow states on the
blade are examined and quantified. The flow states on the rotor blade before
the gust strike at maximum and minimum gust velocity are compared. An
increased blade loading is detectable in the pressure coefficients and
integrated blade loads. The friction force coefficients indicate the dynamic
separation and re-attachment of the flow during the gust. Moreover, a
verification of the method is performed by comparing the rotor torque during
the extreme operating gust to results of FAST rotor code.
Produzindo o sagrado pelas mídias sociais: a interação dos fiéis com o Templo de Salomão no Instagram
Authors: De Oliveira Jênifer Rosa , Cunha Magali Do Nascimento
Published: July 2018

Os imaginários sociais são criações coletivas que permitem que os sujeitos se reconheçam e partilhem seu universo simbólico, e que por isso dão liga a uma sociedade. Este processo constante de apropriação e transmissão dos imaginários alimenta e é alimentado, dentre outras fontes, pela mídia. Neste trabalho, nos propomos a identificar como as mídias sociais atuam nesse processo coletivo de reapropriação dos imaginários sobre o sagrado ao permitir que os usuários interajam com o conteúdo compartilhado e também entre si, estimulando a formação de vínculos afetivos. Para fundamentar a compreensão deste processo comunicacional, recorremos às Teorias do Imaginário. A trajetória metodológica inclui um estudo do perfil do Templo de Salomão da Igreja Universal do Reino de Deus no Instagram, por meio de análise iconográfica de fotografias com o maior número de "curtidas", postadas nos mêses posteriores à inauguração, combinada com uma interpretação dos comentários dos fiéis referentes a elas.
O LUGAR NO ENSINO DE GEOGRAFIA: reflexões a partir de Paulo Freire e Milton Santos
Authors: Carneiro Mauricio Barbosa
Published: July 2018

Esta análise se propôs a compreender os sentidos do Lugar no ensino de geografia a partir das reflexões de Freire (Ideologia e Educação: reflexões sobre a não neutralidade da Educação, 1981; Sobre Educação (Diálogos), 1984; Pedagogia do oprimido, 1987; Educação como prática da liberdade, 2007; Pedagogia da autonomia: saberes necessários à prática educativa, 1996) e Santos (A natureza do espaço, 2012a; Da Totalidade ao Lugar, 2014; Por uma outra globalização: do pensamento único à consciência universal, 2015). O objetivo principal foi investigar como esses autores retratam o lugar nos seus escritos a partir da abordagem qualitativa. Entende-se que esse lugar precisa se conectar à realidade vivida pelos educandos e que o mesmo se relaciona a outras escalas geográficas, como o espaço e a paisagem. Considera-se que esse mesmo processo de entender o lugar no ensino é uma construção social e histórica diante de uma realidade passível de ser compreendida e transformada. O trabalho baseia-se em pressupostos da teoria da aprendizagem crítica libertadora de Freire e na geografia crítica de Santos, considerando crucial o viés histórico dialético para compreensão dos antagonismos presentes no espaço vivido. Aborda as práticas educativas do ensino de Geografia a partir de uma realidade comum aos sujeitos. Entende que esses sujeitos são capazes de compreender a sua realidade e nela atuar para a transformação do espaço onde vivem. Há, portanto, a necessidade de identificar nos contextos das escolas as diversas geografias do lugar, permitindo a aproximação dos conceitos estudados com a realidade vivida pelos sujeitos.
O “TORÉ” E O ENSINO DE GEOGRAFIA: as músicas indígenas na etnoeducação Potiguara da Paraíba
Authors: Silva Sidnei Felipe da , Ramos Leandro Da Silva
Published: July 2018

A música é de suma importância para os povos indígenas Potiguara da Paraíba. Ela está presente no cotidiano desses povos, seja nos rituais, na pesca, na caça, na religião, nas plantações, nas atividades domésticas e em outros momentos que constituem o processo de produção do espaço da etnia. O Toré e suas melodias apresenta temáticas significativas para a geografia escolar, tais como: a questão territorial, a dinâmica natural (vegetação, clima, relevo, hidrografia), e a riqueza cultural e religiosa desses povos. A abordagem do Toré, como recurso didático-pedagógico no ensino de geografia nas escolas de educação diferenciada da etnia Potiguara tem como objetivo geral facilitar o ensino-aprendizagem de temáticas geográficas e (re)afirmar a identidade étnica e cultural. A metodologia proposta para esta ação pauta-se pela pesquisa bibliográfica sobre a Etnoeducação e a Geografia escolar por meio da análise documental dos Referenciais Curriculares para a Educação Indígena (RCNEI, 2005); apresenta abordagem qualitativa, por focar no caráter subjetivo do objeto, compreendendo suas particularidades.
O ESTÁGIO OBRIGATÓRIO NO CURSO DE GEOGRAFIA NA UEG CÂMPUS FORMOSA: um componente instigando a formação crítica e reflexiva?
Authors: Souza Francilane Eulália de
Published: July 2018

Posto que o estágio é momento privilegiado de experimentação docente, o mesmo precisa estar alicerçado em teorias e práticas que possibilitam ao aluno pensar a si mesmo numa perspectiva investigativa da sua própria ação. O objetivo desse artigo é apresentar o caminhar do estágio supervisionado obrigatório, desenvolvido no curso de licenciatura em Geografia da UEG Câmpus Formosa, para uma perspectiva investigativa e crítica da formação docente. A principal metodologia foi a pesquisa bibliográfica e documental, assim como a pesquisa de campo. As teorias da representação social foram aqui tomadas como instrumento para analisar como alunos vêm representando o estágio supervisionado. Por fim, embora esse componente tenha apresentado uma transformação qualitativa, ainda podemos afirmar que suas práxis carecem de ações alicerçadas no diálogo entre os sujeitos que executam esse componente pedagógico para, assim, superar os desafios ainda presentes.
Políticas linguísticas e a língua de sinais brasileira
Authors: Júnior Josmar Gonçalves , Dórea Yasmin Galvani Tonete , Kogut Marcos Kluber , Souza Luiz Cláudio da Silva
Published: July 2018

Este estudo tem como objetivo apresentar algumas reflexões sobre as políticas lingüísticas e a Língua Brasileira de Sinais (Libras). Também aborda o plurilinguismo, na tentativa de identificar a relação entre línguas e poder. O que justifica tal empreitada é a percepção da necessidade de criação de políticas linguísticas que promovam a difusão da Libras, para que mais pessoas possam conhecê-la. A pesquisa foi realizada por meio de entrevistas com alunos surdos, estudantes do curso de Letras: Libras da Faculdade de Letras da Universidade Federal de Goiás (UFG), Goiânia. Espera-se que as considerações apresentadas possam contribuir para novas reflexões sobre o plurilinguismo, que é um fato em vários países, dentre os quais o Brasil.
O ensino de libras nos cursos de formação de professores: desafios e possibilidades
Authors: Paiva Gláucia Xavier dos Santos , Faria Juliana Guimarães , Chaveiro Neuma
Published: July 2018

O ensino de Libras nos cursos de formação de professores é obrigatório, conforme estabelecido pela Legislação brasileira. Contudo, ainda há discussões sobre os conteúdos e a carga horária dessas disciplinas. O objetivo deste trabalho é expor algumas reflexões sobre o ensino da Língua Brasileira de Sinais (Libras) nos cursos de Licenciatura. As considerações aqui apresentadas são fruto de um estudo bibliográfico de cunho qualitativo e encontram-se dispostas em duas seções “A Libras como disciplina obrigatória: desafios encontrados” e “Libras nas Licenciaturas: vislumbrando possibilidades”. Nossas considerações finais não pretendem esgotar o tema, tampouco temos a intenção de apontar um único caminho. O intento deste trabalho é, antes de tudo, contribuir para o crescimento qualitativo do processo em questão, alertando para a necessidade de ampliação do debate a respeito do tema.
What is Waste?
Authors: Reno Josh
Published: July 2018

An Arendtian approach to waste is offered which suggests that three common senses of waste refer to products of labor, work, and action, as explained in The Human Condition (1958). The paper offers examples of ecological, utilitarian and moral-political senses of waste, and argues that they are not incommensurable, but form part of a continuum with respect to their relative freedom from constraint. For this reason, different senses of waste offer distinct political dimensions for waste scholars that relate to boundaries between the human/non-human and critiques of oppression and injustice more broadly.
Análisis de indicadores socioculturales de desarrollo rural en la comunidad Santa Rita, Masatepe-Masaya, 2017
Authors: Torres Obando Joseph Orlando
Published: July 2018

Este artículo indaga en las experiencias de otros autores sobre el manejo de indicadores que puedan dar tratamiento a la dimensión sociocultural del desarrollo rural sustentable (dimensión que compete a la parte humana de la sustentabilidad) y, a partir de ello, explorar el estado de desarrollo de la comunidad campesina Santa Rita, ubicada en el municipio de Masatepe, departamento de Masaya. Para ello se utilizó recursos bibliográficos acorde al tema y una metodología cuali-cuantitativa, haciendo uso de encuestas y entrevistas en el contexto antes mencionado. Los resultados arrojaron que un 42% de las familias de Santa Rita se dedican a la producción agrícola, sin embargo, debido a la situación de la tenencia de la tierra, vulnerabilidad ante externalidades climáticas y el acostumbrado uso en grandes cantidades de agroquímicos, hacen de esta actividad una no sustentable, reflejándose en el porcentaje de emigración, el cual indica que en un 54% de las familias locales, por lo menos un miembro de la familia ha tenido que emigrar en los últimos 20 años para ocuparse laboralmente.
Las universidades, modelo de alianza, diálogo y consenso para políticas de ciencia y tecnología
Authors: Canales Salinas Ricardo José , Garcia Morales Narciso
Published: July 2018

El presente artículo, tiene como objetivo visualizar los escenarios viables para formular las políticas de Ciencia y Tecnología de manera participativa e inclusiva. El abordaje de este estudio parte de análisis documental utilizando el enfoque cualitativo sobre la base epistemológica retrospectivo y racionalismo crítico. Se ha encontrado que los actores académicos y no académicos aun operan a un nivel que demanda el rol decidido del estado para convocar y orientar un desempeño más sistémico. Las partes del sistema están ahí y un accionar por muchos años ha mostrado que las acciones en marcha aún son a baja escala y lo que se requiere es escalonar las acciones para activar una formulación de políticas con evidencias empíricas que alimenten la política para construir escenarios dinámicos y ser retome temas estratégicos de la economía nacional. Se concluye que las posibles plataformas de interacción que resulten requieren primero el rol del estado y en segundo lugar llegar a un dialogo entre las partes para establecer un lenguaje de ciencia y tecnología adaptado a la realidad nacional lo que implica no copiar conceptos y enfoques sin antes ser profundamente validados.
Da agência à sustentabilidade: linguagem e prática social em 'RIO+20'
Authors: Martins Ferreira Dina Maria , Cavalcante Antonio Nilson Alves
Published: July 2018

Neste artigo, propomos estabelecer esse mesmo percurso teórico, a partir do ponto de convergência transdisciplinar dos estudos da linguagem, articulando diferentes autores, como Martins Ferreira (2017), Plaza Pinto (2017), Hall (2000), a fim de compreender como conceitos tão caros a esse campo de estudo podem contribuir com o panorama presente diante da sustentabilidade. Apresentamos inicialmente a problemática do consumo (BAUDRILLARD, 2005; DOUGLAS & ISHERWOOD 2009; FEATHERSTONE (1995), MACCRAKENK, 2003) seguida da visão de Boff (2015), Veiga (2013), para então podermos considerar como os conceitos de agência e identidade podem propiciar uma justificação teórica para práticas individuais diante de ideologias que comprometem a manutenção da natureza e ainda analisar o discurso de abertura da conferência Rio+20, no intuito de rastrearmos como a mobilização social é compreendida pela linguagem das autoridades governamentais.
O impeachment de Dilma Rousseff nos editoriais do jornal El País
Authors: Silva Renato Sordi Tolentino da , Sampaio Rafael Cardoso
Published: July 2018

O artigo tem como objetivo analisar o posicionamento do jornal El País, em seus editoriais, sobre o impeachment da ex-presidente Dilma Rousseff. Para a investigação, foi constituído um corpus formado por nove editoriais publicados entre 1o de dezembro de 2015 e 31 de agosto de 2016, período que compreende entre a aceitação da denúncia pela Câmara dos Deputados e o afastamento em definitivo pelo Senado. A metodologia adotada para o desenvolvimento do trabalho foi a Análise de Conteúdo, que foi guiada pelos conceitos de enquadramento e jornalismo cínico. A pesquisa constatou que o El País apresentou a destituição como um processo irregular e um fato essencialmente negativo para o país.