Modeled and Observed Volcanic Aerosol Control on Stratospheric NOy and Cly

Decreases in stratospheric NOx associated with enhanced aerosol have been observed after large volcanic eruptions, for example, after the eruption of Mount Pinatubo in 1991. While the 1991 Mount Pinatubo eruption was the last large explosive eruption, recent studies have shed light on the impacts of moderate-sized eruptions since the year 2000 on the global stratospheric aerosol budget. We use an ensemble of simulations from a coupled climate-chemistry model to quantify and analyze changes in NO and NO2 (NOx), N2O5, HNO3, ClO, and ClONO2 during periods of increased stratospheric volcanic aerosol concentrations since 2000. By using an ensemble approach, we are able to distinguish forced responses from internal variability. We also compare the model ensemble results to satellite measurements of these changes in atmospheric composition, including measurements from the Optical Spectrograph and Infrared Imaging Spectrometer on the Odin satellite and the Aura Microwave Limb Sounder. We find decreases in stratospheric NOx concentrations up to 20 hPa, consistent with increases in stratospheric HNO3 concentrations. The HNO3 perturbations also extend higher, up to 5 hPa, associated with periods of increased volcanic aerosol concentrations in both model simulations and observations, though correlations with volcanic aerosol are considerably higher in the model simulations. The model simulates increases in ClO at altitudes and magnitudes similar to the NOx reductions, but this response is below the detectable limit in the available observations (100 pptv). We also demonstrate the value of accounting for transport-related anomalies of atmospheric trace gases by regression onto N2O anomalies

The G4Foam Experiment: global climate impacts of regional ocean albedo modification

Reducing insolation has been proposed as a geoengineering response to global warming. Here we present the results of climate model simulations of a unique Geoengineering Model Intercomparison Project Testbed experiment to investigate the benefits and risks of a scheme that would brighten certain oceanic regions. The National Center for Atmospheric Research CESM CAM4-Chem global climate model was modified to simulate a scheme in which the albedo of the ocean surface is increased over the subtropical ocean gyres in the Southern Hemisphere. In theory, this could be accomplished using a stable, nondispersive foam, comprised of tiny, highly reflective microbubbles. Such a foam has been developed under idealized conditions, although deployment at a large scale is presently infeasible. We conducted three ensemble members of a simulation (G4Foam) from 2020 through to 2069 in which the albedo of the ocean surface is set to 0.15 (an increase of 150 %) over the three subtropical ocean gyres in the Southern Hemisphere, against a background of the RCP6.0 (representative concentration pathway resulting in +6 W m⁻² radiative forcing by 2100) scenario. After 2069, geoengineering is ceased, and the simulation is run for an additional 20 years. Global mean surface temperature in G4Foam is 0.6 K lower than RCP6.0, with statistically significant cooling relative to RCP6.0 south of 30° N. There is an increase in rainfall over land, most pronouncedly in the tropics during the June–July–August season, relative to both G4SSA (specified stratospheric aerosols) and RCP6.0. Heavily populated and highly cultivated regions throughout the tropics, including the Sahel, southern Asia, the Maritime Continent, Central America, and much of the Amazon experience a statistically significant increase in precipitation minus evaporation. The temperature response to the relatively modest global average forcing of −1.5 W m⁻² is amplified through a series of positive cloud feedbacks, in which more shortwave radiation is reflected. The precipitation response is primarily the result of the intensification of the southern Hadley cell, as its mean position migrates northward and away from the Equator in response to the asymmetric cooling

RESILIENCE ASSESSMENT OF MICROGRIDS TRANSITIONING TO MULTI-MICROGRIDS IN RURAL AREAS

Electrification is a priority for many countries, such as those seeking to achieve the United Nations Sustainable Development Goal 7, which focuses on supplying affordable, reliable, and sustainable energy for all. The use of Renewable Energy Sources (RES) to design off-grid Microgrids (MGs) in rural areas significantly contributes toward achieving this goal, especially as the MGs are eventually interconnected to form more extensive and reliable multi-MGs. However, due to their remote locations (e.g., resulting in longer time before support can reach the areas), MGs are particularly susceptible to weather shocks (e.g., Windstorms), and even if their transition to multi-MGs makes them more reliable, it is unclear if their resilience will also improve. To tackle this research question, this paper proposes an MG resilience assessment methodology which brings together (i) linear programming optimisation of energy resources to capture the use of RES with (ii) Sequential Monte Carlo simulations (SMCS) to capture the stochastic impacts of Windstorms on different MGs and multi-MGs configurations. The results, based on studies formulated with real data from the Sarawak area in Malaysia, show that even though the resilience of MGs can be improved by interconnecting them, the improvements can be limited if the interconnectors are prone to being impacted by extreme shocks.</p

E-learning to Improve Healthcare Professionals' Attitudes and Practices on Breastfeeding

Breastfeeding training has a crucial role in increasing healthcare professionals' attitudes and in improving professional support for breastfeeding. The collaboration between the Italian National Institute of Health, UNICEF, and the Local Health Authority of Milan has led to the development of an online course on lactation and infant feeding practices