The Chemical and Dynamical Responses of Ozone and Nitrogen Dioxide to the Eruption of Mt. Pinatubo

Observations have shown that the concentration of nitrogen dioxide decreased in both hemispheres in the years following the eruption of Mt. Pinatubo. In contrast, the observed ozone response was largely asymmetrical with respect to the equator, with a decrease in the northern hemisphere and little or no change in the southern hemisphere. Simulations including enhanced heterogeneous chemistry due to the presence of the volcanic aerosol reproduce a decrease of ozone in the northern hemisphere, but also produce a comparable ozone decrease in the southern hemisphere contrary to observations. Our simulations show that the heating due to the volcanic aerosol enhanced both the tropical upwelling and the extratropical downwelling. The enhanced extratropical downwelling, combined with the time of the eruption relative to the seasonal phase of the Brewer-Dobson circulation, increased the ozone in the southern hemisphere and counteracted the ozone depletion due to heterogeneous chemistry on volcanic aerosol

The Response of Ozone and Nitrogen Dioxide to the Eruption of Mt. Pinatubo

Observations have shown that the global mass of nitrogen dioxide decreased in both hemispheres in the year following the eruption of Mt. Pinatubo. In contrast, the observed ozone response was largely asymmetrical with respect to the equator, with a decrease in the northern hemisphere and little change and even a small increase in the southern hemisphere. Simulations including enhanced heterogeneous chemistry due to the presence of the volcanic aerosol reproduce a decrease of ozone in the northern hemisphere, but also produce a comparable ozone decrease in the southern hemisphere, contrary to observations. Our simulations show that the heating due to the volcanic aerosol enhanced both the tropical upwelling and the extratropical downwelling. The enhanced extratropical downwelling, combined with the time of the eruption relative to the phase of the Brewer-Dobson circulation, increased the ozone in the southern hemisphere and counteracted the ozone depletion due to heterogeneous chemistry on volcanic aerosol

The Response of Ozone and Nitrogen Dioxide to the Eruption of Mount Pinatubo

Observations have shown that the global mass of nitrogen dioxide decreased in both hemispheres in the year following the eruption of Mt. Pinatubo, indicating an enhanced heterogeneous chemistry. In contrast, the observed ozone response was largely asymmetrical with respect to the equator, with a decrease in the northern hemisphere and little change in the southern hemisphere. Simulations including enhanced heterogeneous chemistry due to the presence of the volcanic aerosol reproduce a decrease of ozone in the northern hemisphere, but also produce a comparable ozone decrease in the southern hemisphere, contrary to observations. Our simulations show that the heating due to the volcanic aerosol enhanced both the tropical upwelling and the extratropical downwelling. The enhanced extratropical downwelling, combined with the time of the eruption relative to the phase of the Brewer-Dobson circulation, increased the ozone in the southern hemisphere and counteracted the ozone depletion due to heterogeneous chemistry on volcanic aerosol

Identification and analysis of impact factors on the economic feasibility of photovoltaic energy investments

The introduction of environmental impact targets around the world has highlighted the need to adopt alternative sources of energy, which can supply the demand and mitigate the damage caused to the environment. Solar energy is one of the main sources of alternative energy, and is considered an abundant source of clean energy. However, to facilitate and encourage investors interested in the installation of photovoltaic energy systems for electricity production, it is essential to evaluate the factors that impact the economic viability of the projects. Therefore, the objective of this research is to present a systematic analytical framework, in order to identify and analyze the main factors that impact the financial feasibility of projects for the installation of photovoltaic energy plants. For this purpose, a systematic literature review was carried out, analyzing the main studies related to the topic and identifying the main factors that may financially affect investments in photovoltaic energy systems. From this review, 29 influencing factors were identified and separated into five categories, namely, location, economic, political, climatic and environmental, and technical factors. The main factors highlighted are the investment cost, power generation, operation and maintenance costs, solar radiation, lifetime, energy tariff, efficiency, electricity consumption, and interest and taxes. The results may assist policy makers, investors, researchers, and other stakeholders to identify the key factors that are being examined in the literature, and to evaluate which ones should be considered in their study to ensure the sustainable development of power generation through the solar source

Frailty assessment in an unselected population admitted to an intensive cardiac care unit

Abstract Background Although interest in frailty has expanded among cardiology experts over the past 2 decades, its integration, as part of cardiovascular disease management, is still lacking, above all in the acute cardiac care setting. The Clinical Frailty Scale (CFS) is a brief guided tool to assess frailty in hospital settings without specialist equipment. Purpose Our objective was to test the performance of the CFS in an older, unselected population, admitted to an Intensive Cardiac Care Unit (ICCU) during the year 2019. Methods The study sample included 431 patients ≥65 years old, admitted to an ICCU of a tertiary cardiac center in Italy. The CFS ranged from "very fit: 1" to "terminally ill: 9", but it was considered present at a score ≥5. Our primary endpoint was defined by a combination of severe complications requiring critical care and in-hospital death. The data were collected from the hospital discharge summary and the electronic chart records. Results 158 patients (36.7%) were frail. These individuals had greater comorbidity and higher in-hospital mortality (Table 1). After a multivariable logistic regression analysis, 4 predictors were identified: signs of congestive heart failure (OR: 8.51, 95% Confidence Interval-CI: 4.63–14.6; p<0,001), systolic blood pressure (OR per 1 mmHg increasing: 0.98, 95% CI: 0.97–0.99; p<0,001), smoking habit (OR: 0.49, 95% CI: 0.22–1.11; p=0.09) and the CFS ≥5 (OR: 1.86, 95% CI: 1.08–3.23: p=0,026). Conclusions The CFS is a simple guided frailty tool that may enhance outcome prediction in the acute cardiac care setting. These findings merit evaluation in larger cohorts of unselected patients. Funding Acknowledgement Type of funding sources: None

The MESSy aerosol submodel MADE3 (v2.0b): description and a box model test

We introduce MADE3 (Modal Aerosol Dynamics model for Europe, adapted for global applications, 3rd generation; version: MADE3v2.0b), an aerosol dynamics submodel for application within the MESSy framework (Modular Earth Submodel System). MADE3 builds on the predecessor aerosol submodels MADE and MADE-in. Its main new features are the explicit representation of coarse mode particle interactions both with other particles and with condensable gases, and the inclusion of hydrochloric acid (HCl) / chloride (Cl) partitioning between the gas and condensed phases. The aerosol size distribution is represented in the new submodel as a superposition of nine lognormal modes: one for fully soluble particles, one for insoluble particles, and one for mixed particles in each of three size ranges (Aitken, accumulation, and coarse mode size ranges). <br><br> In order to assess the performance of MADE3 we compare it to its predecessor MADE and to the much more detailed particle-resolved aerosol model PartMC-MOSAIC in a box model simulation of an idealised marine boundary layer test case. MADE3 and MADE results are very similar, except in the coarse mode, where the aerosol is dominated by sea spray particles. Cl is reduced in MADE3 with respect to MADE due to the HCl / Cl partitioning that leads to Cl removal from the sea spray aerosol in our test case. Additionally, the aerosol nitrate concentration is higher in MADE3 due to the condensation of nitric acid on coarse mode particles. MADE3 and PartMC-MOSAIC show substantial differences in the fine particle size distributions (sizes &lesssim; 2 μm) that could be relevant when simulating climate effects on a global scale. Nevertheless, the agreement between MADE3 and PartMC-MOSAIC is very good when it comes to coarse particle size distributions (sizes &gtrsim; 2 μm), and also in terms of aerosol composition. Considering these results and the well-established ability of MADE in reproducing observed aerosol loadings and composition, MADE3 seems suitable for application within a global model

Influence of the Mt. Pinatubo Eruption on the Stratospheric Circulation

On June 15th, 1991 the eruption of Mt. Pinatubo in the Philippines injected about 20 Tg of sulfur dioxide in the stratosphere, which was transformed into sulfuric acid aerosol. Even though stratospheric winds climatologically tend to hinder the air mixing between the two hemispheres, observations have shown that a large part of the SO2 emitted by Mt. Pinatubo have been transported from the Northern to the Southern Hemisphere. We show how the absorption of radiation by sulfate aerosol is responsible for the spreading to the southern hemisphere through a middle stratospheric channel. We simulate the eruption of Mt. Pinatubo with the Goddard Earth Observing System (GEOS) version 5 general circulation model, coupled to the aerosol module GOCART and the stratospheric chemistry module StratChem. Our simulations are in good agreement with SAGE-II and AVHRR data. We perform two ensembles of simulations: the first ensemble consists of runs without coupling between aerosol and radiation. In these simulations the plume of aerosols is treated as a passive tracer and the atmosphere is unperturbed. In the second ensemble of simulations aerosols and radiation are coupled. We show that the set of runs with interactive aerosol produces a larger cross-equatorial transport of the Pinatubo cloud, in agreement with the observations. At first, the volcanic cloud is transported from the latitude of the eruption to both hemispheres through a lower stratospheric pathway. Additionally, in the interactive simulations the absorption of long wave radiation from the volcanic sulfate induces a lofting of the cloud to the middle atmosphere and, at the same time, a divergent motion from the center of the cloud. Such motion spreads the volcanic cloud across the equator and to the tropics, where the background circulation carry it to higher latitudes

Dispersion of the Volcanic Sulfate Cloud from the Mount Pinatubo Eruption

We simulate the transport of the volcanic cloud from the 1991 eruption of Mount Pinatubo with the GEOS-5 general circulation model. Our simulations are in good agreement with observational data. We tested the importance of initial condition corresponding to the specific meteorological situation at the time of the eruption by employing reanalysis from MERRA. We found no significant difference in the transport of the cloud. We show how the inclusion of the interaction between volcanic sulfate aerosol and radiation is essential for a reliable simulation of the transport of the volcanic cloud. The absorption of long wave radiation by the volcanic sulfate induces a rising of the volcanic cloud up to the middle stratosphere, combined with divergent motion from the latitude of the eruption to the tropics. Our simulations indicate that the cloud diffuses to the northern hemisphere through a lower stratospheric pathway, and to mid- and high latitudes of the southern hemisphere through a middle stratospheric pathway, centered at about 30 hPa. The direction of the middle stratospheric pathway depends on the season. We did not detect any significant change of the mixing between tropics and mid- and high latitudes in the southern hemisphere

The Response of Ozone and Nitrogen Dioxide to the Eruption of Mount Pinatubo at Southern and Northern Midlatitudes

Observations have shown that the mass of nitrogen dioxide decreased at both southern and northern midlatitudes in the year following the eruption of Mt. Pinatubo, indicating that the volcanic aerosol had enhanced nitrogen dioxide depletion via heterogeneous chemistry. In contrast, the observed ozone response showed a northern midlatitude decrease and a small southern midlatitude increase. Previous simulations that included an enhancement of heterogeneous chemistry by the volcanic aerosol but no other effect of this aerosol produce ozone decreases in both hemispheres, contrary to observations. The authors simulations show that the heating due to the volcanic aerosol enhanced both the tropical upwelling and Southern Hemisphere extratropical downwelling. This enhanced extratropical downwelling, combined with the time of the eruption relative to the phase of the Brewer Dobson circulation, increased Southern Hemisphere ozone via advection, counteracting the ozone depletion due to heterogeneous chemistry on the Pinatubo aerosol