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 [‘FPI-SO’ grant: SVP-2013- 067953].Peer ReviewedPostprint (published version

Estudi i implementació d'un assistent de veu independent del núvol

Aquest estudi té com a finalitat principal aconseguir que l’assistent de veu Mycroft funcioni de forma independent al núvol i que pugui operar sense necessitat d’estar connectat a internet. Aquestes necessitats impliquen que els diferents servidors que permeten el funcionament de l’assistent funcionin de forma local al dispositiu i disposin de totes les dades necessàries per operar

La oportunidad aseguradora en el sector de las energías renovables

Màster de Direcció d'Entitats Asseguradores i Financeres, Universitat de Barcelona, Facultat d'Economia i Empresa, Curs: 2008-2009, Tutor: Manuel Martínez RodríguezLa presente tesis plantea las dificultades con las que se encuentra, actualmente, la economía mundial con respecto a la dependencia energética de los combustibles fósiles. Asimismo, se pone de manifiesto la importante implicación medioambiental producida por el uso intensivo de este tipo de combustibles. De ello, la solución adoptada pasa por extender la utilización de la tecnología de las energías renovables de forma tal que sea factible una distribución energética mucho más diversificada y un suministro energético 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 específica a estas tecnologías relativamente nuevas. La oportunidad de negocio de las entidades aseguradoras será considerada como tal en la medida en que se evalúen 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 específico

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

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 Organization’s (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