188 research outputs found
Aerosol-radiation interaction in atmospheric models: Idealized sensitivity study of simulated short-wave direct radiative effects to particle microphysical properties
We assessed the impact of the microphysical parameterization of natural and anthropogenic aerosols on simulated short-wave radiative effects due to Aerosol-Radiation Interaction (ARI). Layer radiative properties (optical depth, single scattering albedo and asymmetry factor) of dry mineral dust, organic carbon and a black carbon-sulfate mixture have been calculated with a T-matrix code in the short-wave spectral region, after perturbing relevant particle microphysical properties (size distribution, refractive index, mixing state). For each aerosol species, an idealized atmospheric layer and three events of increasing intensity have been set. Then, short-wave direct radiative effects (clear-sky) have been simulated at the top-of-atmosphere (TOA) and at surface (SFC) using the radiative transfer model RRTMG_SW (widely used in atmospheric models), separately for each aerosol species. We observed considerably variable impacts of the particle microphysical perturbations on the layer radiative properties for mineral dust and organic carbon, mainly due to the different sizes of the two species. For the black carbon-sulfate mixture, the single scattering albedo has been found to be much lower in the internal mixing case. Regarding the direct radiative effects, we observed perturbation-induced variability ranges (evaluated against the base net fluxes in absence of aerosols) always within the perturbation range set for the particle microphysical properties . This work, therefore, quantitatively demonstrates that small uncertainties on the aerosol microphysical parameterization propagate on the simulated direct radiative effects mainly with a loss of strength. Considerable perturbation-induced absolute variations of the direct radiative effects have been found (above all for large aerosol amounts), which could significantly affect the model assessments of the ARI radiative effects and therefore meteorological forecasts and climate predictions.This work has been funded by the Spanish Ministry of Economy and Competitiveness [grant: CGL2013-46736-R] and by the
ACTRIS Research Infrastructure Project of the European Union's Horizon 2020 research and innovation programme [grant agreement:
No. 654169]. Further support has been provided by the Severo Ochoa Program, awarded by the Spanish Government [grant:
SEV-2011-00067]. Vincenzo Obiso is funded by the Spanish Ministry of Economy and Competitiveness [âFPI-SOâ grant: SVP-2013-
067953].Peer ReviewedPostprint (published version
Estudi i implementaciĂł d'un assistent de veu independent del nĂșvol
Aquest estudi tĂ© com a finalitat principal aconseguir que lâassistent de veu Mycroft
funcioni de forma independent al nĂșvol i que pugui operar sense necessitat dâestar
connectat a internet. Aquestes necessitats impliquen que els diferents servidors que
permeten el funcionament de lâassistent funcionin de forma local al dispositiu i disposin
de totes les dades necessĂ ries per operar
La oportunidad aseguradora en el sector de las energĂas renovables
MĂ ster de DirecciĂł d'Entitats Asseguradores i Financeres, Universitat de Barcelona, Facultat d'Economia i Empresa, Curs: 2008-2009, Tutor: Manuel MartĂnez RodrĂguezLa presente tesis plantea las dificultades con las que se encuentra, actualmente, la economĂa mundial con respecto a la dependencia energĂ©tica de los combustibles fĂłsiles. Asimismo, se pone de manifiesto la importante implicaciĂłn medioambiental producida por el uso intensivo de este tipo de combustibles. De ello, la soluciĂłn adoptada pasa por extender la utilizaciĂłn de la tecnologĂa de las energĂas renovables de forma tal que sea factible una distribuciĂłn energĂ©tica mucho mĂĄs diversificada y un suministro energĂ©tico limpio y eficiente.
El retorno de las inversiones requeridas para tal fin necesita de ciertas medidas que aporten seguridad a promotores, propietarios y consumidores de una manera especĂfica a estas tecnologĂas relativamente nuevas. La oportunidad de negocio de las entidades aseguradoras serĂĄ considerada como tal en la medida en que se evalĂșen los posibles riesgos, se consideren las medidas preventivas precisas, se aporte una oferta aseguradora adecuada y, si procede, se gestione eficazmente un tipo de siniestro muy especĂfico
Local traffic contribution to black carbon horizontal and vertical profiles in compact urban areas
Urban air pollution is characterized by strong spatial gradients
produced by the presence of heavily trafficked streets. Given the
negative health effects of air pollution, decision makers are
implementing policies to reduce air pollution by modifying traffic
flows near activity patterns of vulnerable populations. However, to our
knowledge, there is quite a lack of appropriate decision tools to
support such modifications at neighborhood to street levels. Measured
horizontal and vertical distributions of traffic air pollutants can help
understanding the variation of concentrations at increasing distances
from emitting roads. Yet, models are still necessary to estimate the
contribution of local traffic to measured concentrations.
The main objective of this work is to investigate the contribution of
local traffic to black carbon horizontal and vertical profiles based on
measurements and model simulations. We will discuss the degree of
influence of the different streets on black carbon measured profiles in
Barcelona
Ground-level ozone simulations improved by updating land cover databases
Tropospheric ozone (O3) is one of the pollutants which raises great concern to the World Health Organization (WHO) because of the health effects associated with its exposure. It is formed in the atmosphere through non-linear photochemical reactions among carbon monoxide (CO), peroxy radicals generated by the photochemical oxidation of volatile organic compounds (VOCs) and nitrogen oxides (NOX) [1]. High levels of tropospheric ozone cause respiratory malfunction, and a long-term exposure can lead to death [2]. Air Quality Models (AQM) can diagnose and predict air pollutant levels, as well as being a key tool to assess air quality management policies. Nevertheless, modelling ozone surface concentration has several sources of uncertainty, with respect to biogenic and anthropogenic precursor emissions, chemical boundary conditions, chemistry formation, and deposition [3]. Deposition velocity depends on biotic and abiotic parameters that, ultimately, are linked to the land use class (LUC). The use of updated information on land use is critical to improve AQM results. This study assesses the impact of using an updated land cover map on the skills of an AQM simulating surface ozone concentration over Spain. We used the Multiscale Online Nonhydrostatic AtmospheRe CHemistry (MONARCH) model and enhanced the system with new land use information
Cluster Analysis of 4-Day Back Trajectories Arriving in the Barcelona Area, Spain, from 1997 to 2002
Accelerating atmospheric models using GPUs
Environmental models are simplified representations of an
object or a process [1]. These models provide valuable information
on the nature of real-world phenomena and systems
[2], with many applications in science and engineering [3]. For
example, environmental models play an increasingly important
role in understanding the potential implications of climate
change [4].
There are many types of models in the environmental
sciences [5]. These models are often associated with large computational
costs because of their complexity [6]. The model
studied in this work, the Multiscale Online Nonhydrostatic AtmospheRe
CHemistry model (MONARCH), is an atmospheric
model that currently runs in the MareNostrum supercomputer
of the Barcelona Supercomputing Center (BSC), one of the
Top-500 supercomputers in the world [7] [8]. MONARCH
provides regional mineral dust forecasts to the World Meteorological
Organizationâs (WMO) Barcelona Dust Forecast Center
(BDFC) and the Sand and Dust Storm Warning Advisory and
Assessment System (SDS-WAS). MONARCH also provides
global aerosol forecasts to the International Cooperative for
Aerosol Prediction (ICAP) initiative
Testing simple models for street wind conditions in Barcelona
Street wind speed and direction drive models to estimate air quality levels at street scale. In this study, simple models are combined with a mesoscale meteorological model to provide wind conditions at street level. Then, wind speed and direction are evaluated using observations collected during an experimental campaign in April 2013 at street level in Barcelona, Spain. Overall, models considering street geometry give better estimates for both wind speed and direction than those assuming homogeneous terrain. For light winds, models tend to produce a large amount of error estimating wind direction
Impact of aerosol microphysical properties on mass scattering cross sections
We assessed the sensitivity of simulated mass scattering cross sections (αλsca [m2/g]) of three aerosol perturbed particle microphysical properties and derived constraintspecies to on these microphysical properties, suitable for the north-western Mediterranean basin, from a comparison between code calculations and observations. In detail, we calculated αλsca of mineral dust,organic carbon and sulfate at three wavelengths in the visible range with a T-matrix optical code, considering ±20%perturbations on size distribution, refractive index and mass density, and spheroids with two different axial ratios as shape perturbations. Then, we compared the simulation results with a set of observed αλsca of mineral dust, aged organics and ammonium sulfate sources provided by the Institute of Environmental Assessment and Water Research (IDAEA-CSIC) and representative of the north-western Mediterranean Basi
CAMP first GPU solver: a solution to accelerate chemistry in atmospheric models
Atmospheric models are a representation of dynamical, physical, chemical, dynamical, and radiative processes in the atmosphere [1]. The load of these models is often spread across multiple processes in HPC environments. Most of this load comes from the resolution of chemical processes, which can take up to 90% of the total time execution [2]. Recent studies reported a relevant speedup by translating a chemical module to GPUs [3] [4]. This study is based in some previous works of the authors. These works are tested in the Chemistry Accross Multiple Phases (CAMP) module [5] simulating the conditions of an atmospheric model experiment. In our first approach we present an strategy to efficiently integrate GPU routines without needing to translate the entire chemical module to GPU code [6]. In our second and last work, we integrated a GPU version of the linear solver used in CAMP and evaluated multiple kernel configurations, achieving up to 34x speedup from the base CPU linear solver in a singlethread execution, in addition to a 2.7x for an equivalent MPI implementation with the maximum number of physical cores available on a node (40) [7]. The main objective of this work is to develop a GPU version of the entire CAMP solving algorithm. Our second objective is to evaluate the performance of our work, comparing the results with other state of the art GPU chemical modules
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