Filipe Duarte Santos

Molecular understanding of sulphuric acid–amine particle nucleation in the atmosphere

Nucleation of aerosol particles from trace atmospheric vapours is thought to provide up to half of global cloud condensation nuclei. Aerosols can cause a net cooling of climate by scattering sunlight and by leading to smaller but more numerous cloud droplets, which makes clouds brighter and extends their lifetimes. Atmospheric aerosols derived from human activities are thought to have compensated for a large fraction of the warming caused by greenhouse gases. However, despite its importance for climate, atmospheric nucleation is poorly understood. Recently, it has been shown that sulphuric acid and ammonia cannot explain particle formation rates observed in the lower atmosphere. It is thought that amines may enhance nucleation, but until now there has been no direct evidence for amine ternary nucleation under atmospheric conditions. Here we use the CLOUD (Cosmics Leaving OUtdoor Droplets) chamber at CERN and find that dimethylamine above three parts per trillion by volume can enhance particle formation rates more than 1,000-fold compared with ammonia, sufficient to account for the particle formation rates observed in the atmosphere. Molecular analysis of the clusters reveals that the faster nucleation is explained by a base-stabilization mechanism involving acid–amine pairs, which strongly decrease evaporation. The ion-induced contribution is generally small, reflecting the high stability of sulphuric acid–dimethylamine clusters and indicating that galactic cosmic rays exert only a small influence on their formation, except at low overall formation rates. Our experimental measurements are well reproduced by a dynamical model based on quantum chemical calculations of binding energies of molecular clusters, without any fitted parameters. These results show that, in regions of the atmosphere near amine sources, both amines and sulphur dioxide should be considered when assessing the impact of anthropogenic activities on particle formation.

Oxidation products of biogenic emissions contribute to nucleation of atmospheric particles.

Out of the Air New-particle formation from gaseous precursors in the atmosphere is a complex and poorly understood process with importance in atmospheric chemistry and climate. Laboratory studies have had trouble reproducing the particle formation rates that must occur in the natural world. Riccobono et al. (p. 717) used the CLOUD (Cosmics Leaving Outdoor Droplets) chamber at CERN to recreate a realistic atmospheric environment. Sulfuric acid and oxidized organic vapors in typical natural concentrations caused particle nucleation at similar rates to those observed in the lower atmosphere. Experiments in the CLOUD chamber at CERN reproduce particle nucleation rates observed in the lower atmosphere. Atmospheric new-particle formation affects climate and is one of the least understood atmospheric aerosol processes. The complexity and variability of the atmosphere has hindered elucidation of the fundamental mechanism of new-particle formation from gaseous precursors. We show, in experiments performed with the CLOUD (Cosmics Leaving Outdoor Droplets) chamber at CERN, that sulfuric acid and oxidized organic vapors at atmospheric concentrations reproduce particle nucleation rates observed in the lower atmosphere. The experiments reveal a nucleation mechanism involving the formation of clusters containing sulfuric acid and oxidized organic molecules from the very first step. Inclusion of this mechanism in a global aerosol model yields a photochemically and biologically driven seasonal cycle of particle concentrations in the continental boundary layer, in good agreement with observations.

Molecular understanding of atmospheric particle formation from sulfuric acid and large oxidized organic molecules

Significance The formation of nanoparticles by condensable vapors in the atmosphere influences radiative forcing and therefore climate. We explored the detailed mechanism of particle formation, in particular the role of oxidized organic molecules that arise from the oxidation of monoterpenes, a class of volatile organic compounds emitted from plants. We mimicked atmospheric conditions in a well-controlled laboratory setup and found that these oxidized organics form initial clusters directly with single sulfuric acid molecules. The clusters then grow by the further addition of both sulfuric acid and organic molecules. Some of the organics are remarkably highly oxidized, a critical feature that enables them to participate in forming initial stable molecular clusters and to facilitate the first steps of atmospheric nanoparticle formation. Atmospheric aerosols formed by nucleation of vapors affect radiative forcing and therefore climate. However, the underlying mechanisms of nucleation remain unclear, particularly the involvement of organic compounds. Here, we present high-resolution mass spectra of ion clusters observed during new particle formation experiments performed at the Cosmics Leaving Outdoor Droplets chamber at the European Organization for Nuclear Research. The experiments involved sulfuric acid vapor and different stabilizing species, including ammonia and dimethylamine, as well as oxidation products of pinanediol, a surrogate for organic vapors formed from monoterpenes. A striking resemblance is revealed between the mass spectra from the chamber experiments with oxidized organics and ambient data obtained during new particle formation events at the Hyytiälä boreal forest research station. We observe that large oxidized organic compounds, arising from the oxidation of monoterpenes, cluster directly with single sulfuric acid molecules and then form growing clusters of one to three sulfuric acid molecules plus one to four oxidized organics. Most of these organic compounds retain 10 carbon atoms, and some of them are remarkably highly oxidized (oxygen-to-carbon ratios up to 1.2). The average degree of oxygenation of the organic compounds decreases while the clusters are growing. Our measurements therefore connect oxidized organics directly, and in detail, with the very first steps of new particle formation and their growth between 1 and 2 nm in a controlled environment. Thus, they confirm that oxidized organics are involved in both the formation and growth of particles under ambient conditions.

National assessment of human health effects of climate change in Portugal: approach and key findings.

In this study we investigated the potential impact of climate change in Portugal on heat-related mortality, air pollution–related health effects, and selected vectorborne diseases. The assessment used climate scenarios from two regional climate models for a range of future time periods. The annual heat-related death rates in Lisbon may increase from between 5.4 and 6 per 100,000 in 1980–1998 to between 8.5 and 12.1 by the 2020s and to a maximum of 29.5 by the 2050s, if no adaptations occur. The projected warmer and more variable weather may result in better dispersion of nitrogen dioxide levels in winter, whereas the higher temperatures may reduce air quality during the warmer months by increasing tropospheric ozone levels. We estimated the future risk of zoonoses using ecologic scenarios to describe future changes in vectors and parasites. Malaria and schistosomiasis, which are currently not endemic in Portugal, are more sensitive to the introduction of infected vectors than to temperature changes. Higher temperatures may increase the transmission risk of zoonoses that are currently endemic to Portugal, such as leishmaniasis, Lyme disease, and Mediterranean spotted fever.

Uncovering the kiloparsec-scale stellar ring of NGC 5128 ,

We reveal the stellar light emerging from the kiloparsec-scale, ring-like structure of the NGC 5128 (Centaurus A) galaxy in unprecedented detail. We use arcsecond-scale resolution near infrared images to create a “dust-free” view of the central region of the galaxy, which we then use to quantify the shape of the revealed structure. At the resolution of the data, the structure contains several hundreds of discreet, point-like or slightly elongated sources. The typical extinction-corrected surface brightness of the structure is KS ≈ 16. 5m ag/arcsec 2 , and we estimate the total near infrared luminosity of the structure to be M ≈− 21 mag. We use diffraction limited (FWHM resolution of ≈0.1 �� , or 1.6 pc) near infrared data taken with the NACO instrument on the VLT to show that the structure decomposes into thousands of separate, mostly point-like sources. According to the tentative photometry, the most luminous sources have MK ≈− 12 mag, making them red supergiants or relatively low-mass star clusters. We also discuss the large-scale geometry implied by the reddening signatures of dust in our near infrared images.

Impacts and adaptation to climate change in the Mediterranean coastal areas: the CIRCLE-MED initiative

The Mediterranean region is considered one of the world’s climate change hot spots (Giorgi 2006; Diffenbaugh et al. 2007; Garcı́a et al. 2011). Observations in the Mediterranean area over the last decades indicate clear signs of a changing climate. Statistically significant increasing trends in heat waves and decreasing trends in cold spells have been reported (Kuglitsch et al. 2009, 2010). The land area surrounding the Mediterranean has experienced ten of the twelve driest winter seasons since 1902 in just the last 20 years (Hoerling et al. 2011). The more frequent droughts, together with heat-related stresses, are also contributing to increased tree mortality (Allen et al. 2010; Bertini et al. 2011) and forest fires (Pausas and Fernández-Muñoz 2012) in the Mediterranean region, further exacerbating desertification that is already occurring in parts of the region. Models foresee major future changes in climate and related direct impacts in the area, such as marked increases in temperatures, strong decreases in rainfall (Garcı́a et al. 2011), and sea-level rise (Rahmstorf et al. 2011). Many Mediterranean socioeconomic sectors are vulnerable to these climatic changes. The projected decrease in precipitation is very likely to limit the water availability, which is already a problem in many parts of the region, particularly for agriculture, which consumes 60 % to more than 80 % of the water supply (EEA 2009). Climate change in the Mediterranean will increase the need for irrigation in agriculture, but future irrigation will be constrained by reduced runoff, reduced recharge of aquifers, and competition from other sectors, in particular human settlements and energy. The pressure on available water resources and consequent risk of overexploitation is therefore likely to increase. Coastal areas are specifically vulnerable to climate change, a major driver of which being sea-level rise (SLR), which has already been taking place in the past decades. In the northwest Mediterranean, the average SLR rate between 1990 and 2010 was 3.4 mm year (Calvo et al. 2011). SLR is expected to accelerate in the future, e.g., predicted to be in the range of 0.62–1.48 m up to 2100 by the RCP4.5 scenario (Rahmstorf et al. 2011). For coastal impact studies, the appropriate variable is local relative SLR that is also determined by the subsidence of coastal land, subsurface resource extraction, glacial isostatic rebound, and tectonic movements. The major impacts of SLR are changes in coastal wetlands, increased coastal flooding and erosion, and saltwater intrusion into estuaries and deltas. More frequent and severe weather and climatic events will further enhance these phenomena in the short term, whereas on longer timescales changes in wind and wave climate can interfere with sediment transport leading to greater erosion or accretion. Other concerns, particularly for the coastal ecosystems, are an increase in seawater temperature and acidity. In the Mediterranean, sea surface temperatures have increased 0.43 C from 1957 to 2008 (Belkin 2009). Periods of extreme seawater temperature have contributed to F. D. Santos T. C. Lourenço SIM-CCIAM, Faculty of Sciences, University of Lisbon, Lisbon, Portugal e-mail: fdsantos@siam.fis.fc.ul.pt

Near infrared imaging of NGC 2316

Harvard-Smithsonian Center for Astrophysics, CfA, U.S.A.e-mail:clada@cfa.harvard.eduAbstract. In the present paper we present JHK photometric results of the young embedded cluster NGC2316. We constructthe cluster radial profile from which we determine a radius of 0.63pc. We find 189 ±29 cluster members in an extinctionlimited sub-sample of the survey, 22±19 of which are possibly substellar. An average extinction of 4.5 visual magnitudes isderived using (H − K) colours of control fields. This extinction is due to the pres ence of residual parental molecular cloud.NGC2316 presents 16% source fraction of excess emission which is consistent with other results from clusters with an age of 2– 3Myr. This age is consistent with the distribution of sources in the colour-magnitude diagram when compared to theoreticalisochrones, and the overall shape of the cluster KLF. The substellar population of the cluster is similar or smaller than thatobserved for other embedded clusters and the stellar objects dominate the cluster membership.Key words. Stars:Formation – Stars:low-mass,brown dwarfs – Stars:planetary systems:protoplanetary disks – Stars:luminosityfunction – Infrared:Stars – ISM:Individual objects (NGC23 16)

Participation, scenarios and pathways in long-term planning for climate change adaptation

Abstract This article describes a climate change adaptation planning process triggered by a group of researchers and stakeholders in a context where no collective responses or long-term plans for protecting a vulnerable coastal system had been initiated, despite local perceptions of vulnerability and risk. The case study shows the application of two methods: scenario workshops and adaptation pathways in the context of a participatory action research methodological design. Participatory action research and qualitative scenario methods are highlighted as accelerators of climate change adaptation processes by calling to action, facilitating and connecting diverse social groups with a stake in a long-term plan towards a more adapted society. The experience leads to the conclusion that planning climate change adaptation has to go far beyond the technical dimension and take into account those affected (in the present and the future) by decisions made. A holistic approach to climate change adaptation planning will depend on the interrelations of managerial and top-down approaches with localized initiatives driven through an inclusive and collective action research process.

Alterações climáticas, sociais e políticas em Portugal: processos de governança num litoral em risco

The Portuguese coast is one of the most threatened by coastal erosion in Europe, a phenomenon that will be intensified by climate change, due to sea level rise and changes in the wave system in the Atlantic coast. Along with this physical fragility, the coast has witnessed an accelerated urban and tourist pressure, which increased in Portugal since the 60s. This phenomenon creates social fragility, which in turn links with a political fragility resulting from the states inability to deal with coastal management in a consistent way. The main response to coastal problems has been investing in heavy defence structures strongly supported by EU funds. However, this type of investment is increasingly compromised due to the economic downturn and the prospective reduction of European funds. Based on three case studies - in the North, Centre and South of Portugal - we will address the current social condition of risk perception in three unstable areas of the Portuguese coast, where urban centres with a strong touristic motivation were installed: Vagueira, Costa da Caparica and Quarteira. Despite having in common recent growth dynamics, these areas show different occupation processes and different levels of coastal erosion. The paper addresses these three places from the point of view of its administrative condition and the effects of public policies for coastal planning. Furthermore we propose a reflexion about the need for new institutional models of governance and sustainable coastal management.

Statistical approach to estimate the impact of climate change on daily ozone concentrations

Short-term exposure to ozone is a public health concern worldwide. Surface ozone is a secondary air pollutant, formed primarily through a complex series of photochemical reactions between nitrogen oxides and reactive hydrocarbons. Hot days with clear skies favour ozone production. Hence, a warmer climate is likely to increase ozone ambient concentration and consequently, the impact of ozone-related health effects. In this paper, we present a statistical model that was developed using an additive mixed modelling approach to estimate daily ozone concentrations based on ground level climate variables, ozone precursors and synoptic atmosphere variables from the National Centre of Environmental Prediction. Two future scenarios (A2a and B2a) of daily ozone concentrations were obtained using the global circulation model HadCM3 taking also into account local per capita ozone precursor’s emissions and population growth for each scenario. Results showed an overall increasing tendency in both scenarios in the averag...