Anthropogenic aerosol forcing - insights from multiple estimates from aerosol-climate models with reduced complexity

This study assesses the change in anthropogenic aerosol forcing from the mid-1970s to the mid-2000s. Both decades had similar global-mean anthropogenic aerosol optical depths but substantially different global distributions. For both years, we quantify (i) the forcing spread due to model-internal variability and (ii) the forcing spread among models. Our assessment is based on new ensembles of atmosphere-only simulations with five state-of-the-art Earth system models. Four of these models will be used in the sixth Coupled Model Intercomparison Project (CMIP6; Eyring et al., 2016). Here, the complexity of the anthropogenic aerosol has been reduced in the participating models. In all our simulations, we prescribe the same patterns of the anthropogenic aerosol optical properties and associated effects on the cloud droplet number concentration. We calculate the instantaneous radiative forcing (RF) and the effective radiative forcing (ERF). Their difference defines the net contribution from rapid adjustments. Our simulations show a model spread in ERF from -0.4 to -0.9 W m(-2). The standard deviation in annual ERF is 0.3 W m(-2), based on 180 individual estimates from each participating model. This result implies that identifying the model spread in ERF due to systematic differences requires averaging over a sufficiently large number of years. Moreover, we find almost identical ERFs for the mid-1970s and mid-2000s for individual models, although there are major model differences in natural aerosols and clouds. The model-ensemble mean ERF is -0.54 W m(-2) for the pre-industrial era to the mid-1970s and -0.59 W m(-2) for the pre-industrial era to the mid-2000s. Our result suggests that comparing ERF changes between two observable periods rather than absolute magnitudes relative to a poorly constrained pre-industrial state might provide a better test for a model's ability to represent transient climate changes.Peer reviewe

Sensitivity of aerosol concentrations and cloud properties to nucleation and secondary organic distribution in ECHAM5-HAM global circulation model

The global aerosol-climate model ECHAM5-HAM was modified to improve the representation of new particle formation in the boundary layer. Activation-type nucleation mechanism was introduced to produce observed nucleation rates in the lower troposphere. A simple and computationally efficient model for biogenic secondary organic aerosol (BSOA) formation was implemented. Here we study the sensitivity of the aerosol and cloud droplet number concentrations (CDNC) to these additions. Activation-type nucleation significantly increases aerosol number concentrations in the boundary layer. Increased particle number concentrations have a significant effect also on cloud droplet number concentrations and therefore on cloud properties. We performed calculations with activation nucleation coefficient values of 2×10⁻⁷s⁻¹, 2×10⁻⁶s⁻¹ and 2×10⁻⁵s⁻¹ to evaluate the sensitivity to this parameter. For BSOA we have used yields of 0.025, 0.07 and 0.15 to estimate the amount of monoterpene oxidation products available for condensation. The hybrid BSOA formation scheme induces large regional changes to size distribution of organic carbon, and therefore affects particle optical properties and cloud droplet number concentrations locally. Although activation-type nucleation improves modeled aerosol number concentrations in the boundary layer, the use of a global activation coefficient generally leads to overestimation of aerosol number. Overestimation can also arise from underestimation of primary emissions

Inter-brain synchronization occurs without physical co-presence during cooperative online gaming

Inter-brain synchronization during social interaction has been linked with several positive phenomena, including closeness, cooperation, prosociality, and team performance. However, the temporal dynamics of inter-brain synchronization during collaboration are not yet fully understood. Furthermore, with collaboration increasingly happening online, the dependence of inter-brain phase synchronization of oscillatory activity on physical presence is an important but understudied question. In this study, physically isolated participants performed a collaborative coordination task in the form of a cooperative multiplayer game. We measured EEG from 42 subjects working together as pairs in the task. During the measurement, the only interaction between the participants happened through on-screen movement of a racing car, controlled by button presses of both participants working with distinct roles, either controlling the speed or the direction of the car. Pairs working together in the task were found to have elevated neural coupling in the alpha, beta, and gamma frequency bands, compared to performance matched false pairs. Higher gamma synchrony was associated with better momentary performance within dyads and higher alpha synchrony was associated with better mean performance across dyads. These results are in line with previous findings of increased inter-brain synchrony during interaction, and show that phase synchronization of oscillatory activity occurs during online real-time joint coordination without any physical co-presence or video and audio connection. Synchrony decreased during a playing session, but was found to be higher during the second session compared to the first. The novel paradigm, developed for the measurement of real-time collaborative performance, demonstrates that changes in inter-brain EEG phase synchrony can be observed continuously during interaction

Total sulfate vs. sulfuric acid monomer concenterations in nucleation studies

Sulfuric acid is known to be a key component for atmospheric nucleation. Precise determination of sulfuric-acid concentration is a crucial factor for prediction of nucleation rates and subsequent growth. In our study, we have noticed a substantial discrepancy between sulfuric-acid monomer concentrations and total-sulfate concentrations measured from the same source of sulfuric-acid vapor. The discrepancy of about 1-2 orders of magnitude was found with similar particle-formation rates. To investigate this discrepancy, and its effect on nucleation, a method of thermally controlled saturator filled with pure sulfuric acid (97% wt.) for production of sulfuric-acid vapor is applied and rigorously tested. The saturator provided an independent vapor-production method, compared to our previous method of the furnace (Brus et al., 2010, 2011), to find out if the discrepancy is caused by the production method itself. The saturator was used in a H2SO4-H2O nucleation experiment, using a laminar flow tube to check reproducibility of the nucleation results with the saturator method, compared to the furnace. Two independent methods of mass spectrometry and online ion chromatography were used for detecting sulfuric-acid or sulfate concentrations. Measured sulfuric-acid or total-sulfate concentrations are compared to theoretical predictions calculated using vapor pressure and a mixing law. The calculated prediction of sulfuric-acid concentrations agrees very well with the measured values when total sulfate is considered. Sulfuric-acid monomer concentration was found to be about 2 orders of magnitude lower than theoretical predictions, but with a temperature dependency similar to the predictions and the results obtained with the ion-chromatograph method. Formation rates are reproducible when compared to our previous results with both sulfuric-acid or total-sulfate detection and sulfuric-acid production methods separately, removing any doubts that the vapor-production method would cause the discrepancy. Possible reasons for the discrepancy are discussed and some suggestions include that the missing sulfuric acid is in clusters, formed with contaminants found in most laboratory experiments. One-to-two-order-of-magnitude higher sulfuric-acid concentrations (measured as total sulfate in this study) would contribute to a higher fraction of particle growth rate than assumed from the measurements by mass spectrometers (i.e. sulfuric-acid monomer). However, the observed growth rates by sulfate-containing vapor in this study does not directly imply a similar situation in the field, where sources of sulfate are much more diverse.Peer reviewe

EC-Earth3-AerChem: A global climate model with interactive aerosols and atmospheric chemistry participating in CMIP6

This paper documents the global climate model EC-Earth3-AerChem, one of the members of the EC-Earth3 family of models participating in the Coupled Model Intercomparison Project Phase 6 (CMIP6). EC-Earth3-AerChem has interactive aerosols and atmospheric chemistry and contributes to the Aerosols and Chemistry Model Intercomparison Project (AerChemMIP). In this paper, we give an overview of the model, describe in detail how it differs from the other EC-Earth3 configurations, and outline the new features compared with the previously documented version of the model (EC-Earth 2.4). We explain how the model was tuned and spun up under preindustrial conditions and characterize the model's general performance on the basis of a selection of coupled simulations conducted for CMIP6. The net energy imbalance at the top of the atmosphere in the preindustrial control simulation is on average -0.09 W m-2 with a standard deviation due to interannual variability of 0.25 W m-2, showing no significant drift. The global surface air temperature in the simulation is on average 14.08 ∼ C with an interannual standard deviation of 0.17 ∼ C, exhibiting a small drift of 0.015 ± 0.005 ∼ C per century. The model's effective equilibrium climate sensitivity is estimated at 3.9 ∼ C, and its transient climate response is estimated at 2.1 ∼ C. The CMIP6 historical simulation displays spurious interdecadal variability in Northern Hemisphere temperatures, resulting in a large spread across ensemble members and a tendency to underestimate observed annual surface temperature anomalies from the early 20th century onwards. The observed warming of the Southern Hemisphere is well reproduced by the model. Compared with the ECMWF (European Centre for Medium-Range Weather Forecasts) Reanalysis version 5 (ERA5), the surface air temperature climatology for 1995-2014 has an average bias of -0.86 ± 0.05 ∼ C with a standard deviation across ensemble members of 0.35 ∼ C in the Northern Hemisphere and 1.29 ± 0.02 ∼ C with a corresponding standard deviation of 0.05 ∼ C in the Southern Hemisphere. The Southern Hemisphere warm bias is largely caused by errors in shortwave cloud radiative effects over the Southern Ocean, a deficiency of many climate models. Changes in the emissions of near-term climate forcers (NTCFs) have significant effects on the global climate from the second half of the 20th century onwards. For the SSP3-7.0 Shared Socioeconomic Pathway, the model gives a global warming at the end of the 21st century (2091-2100) of 4.9 ∼ C above the preindustrial mean. A 0.5 ∼ C stronger warming is obtained for the AerChemMIP scenario with reduced emissions of NTCFs. With concurrent reductions of future methane concentrations, the warming is projected to be reduced by 0.5 ∼ C

Characterization of aerosol particle episodes in Finland caused by wildfires in Eastern Europe

We studied the sources, compositions and size distributions of aerosol particles during long-range transport (LRT) PM2.5 episodes which occurred on 12–15 August, 26– 28 August and 5–6 September 2002 in Finland. Backward air mass trajectories, satellite detections of fire areas and dispersion modelling results indicate that emissions from wild- fires in Russia and other Eastern European countries arrived in Finland during these episodes. Elemental analyses using scanning electron microscopy (SEM) coupled with energy dispersive X-ray microanalyses (EDX) showed that the proportions of S-rich particles and agglomerates (agglomeration was caused partly by the sampling method used) increased during the episodes, and they contained elevated fractions of K, indicating emissions from biomass burning. These aerosols were mixed with S-rich emissions from fossil fuel burning during transport since air masses came through polluted areas of Europe. Minor amounts of coarse Ca-rich particles were also brought by LRT during the episodes, and they probably originated from wildfires and/or from Estonian and Russian oil-shale-burning industrial areas. Ion chromatography analysis showed that concentrations of sulphate (SO2− 4 ), total nitrate (NO−3 +HNO3(g)) and total ammonium (NH+4 +NH3(g)) increased during the episodes, but the ratio of the total amount of these ions to PM10 concentration decreased, indicating unusually high fractions of other chemical components. Particle number size distribution measurements with differential mobility particle sizer (DMPS) revealed that concentrations of particles 90–500 nm increased during the episodes, while concentrations of particles smaller than 90 nm decreased. The reduction of the smallest particles was caused by suppressed new particle formation due to vapour and molecular cluster uptake of LRT particles. Our results show that emissions from wildfires in Russian and other Eastern European countries deteriorated air quality of very large areas, even at distances of over 1000 km from the fire areas

Evaluation study of the suitability of instrumentation to measure ambient NH3 concentrations under field conditions

The uncertainties in emissions of ammonia (NH3) in Europe are large, partially due to the difficulty in monitoring of ambient concentrations due to its sticky nature. In the European Monitoring and Evaluation Program (EMEP) the current recommended guidelines to measure NH3 are by coated annular denuders with offline analysis. This method, however, is no longer used in most European countries and each one has taken a different strategy to monitor atmospheric ammonia due to the increase of commercial NH3 monitoring instrumentation available over the last 20 years. In June 2014, a 3 year project funded under the European Metrology Research Programme, “Metrology for Ammonia in Ambient Air” (MetNH3), started with the aim to develop metrological traceability for the measurement of NH3 in air from primary gas mixtures and instrumental standards to field application. This study presents the results from the field intercomparison (15 instruments) which was held in South East Scotland in August 2016 over an intensively managed grassland. The study compared active sampling methods to a meteorological traceable method which was developed during the project with the aim to produce a series of guidelines for ambient NH3 measurements. Preliminary results highlight both the importance of inlets and management of relative humidity in the measurement of ambient NH3 and of the requirement to carry out frequent intercomparison of NH3 instrumentation. Overall, it would be recommended from this study that a WMO-GAW world centre for NH3 would be established and support integration of standards into both routine and research measurements

Аллостатическая нагрузка у пациенток с раком молочной железы

Breast cancer is the most common cancer in women worldwide. However, the allostatic load in breast cancer patients has not been sufficiently studied. Objective: to study the allostatic load in middle-aged and elderly patients with breast cancer. Material and methods. The study included 65 middle-aged and 60 elderly patients with histologically confirmed breast cancer and 45 people aged 60-74 years, who had no breast cancer. The allostatic load was studied in these three groups according to the level: systolic and diastolic blood pressure, total cholesterol, triglycerides, high and low density lipoproteins, glucose, albumins and waist circumference. Results. The allostatic load score was significantly higher in elderly breast cancer patients than in middle-aged breast cancer patients (4.3 ± 0.3 points versus 2.9 ± 0.2 points, p<0.01). In addition, the allostatic load score in the middle-aged patients with breast cancer was significantly higher (2.7 ± 0.2 points) than in people of the same age, who had no breast cancer (1.6 ± 0.1 points). In elderly patients, the allostatic load score was also significantly higher in patients with breast cancer than in people without breast cancer (4.3 ± 0.3 points and 2.9 ± 0.2 points, respectively; p<0.001). Significant differences in the allostatic load parameters, such as the levels of total cholesterol (5.8 ± 1.3 mmol/l versus 4.0 ± 0.8 mmol/l), and albumin (45.1 ± 7.4 % versus 61.4 ± 7.6 %) were found between breast cancer patients aged 60-74 years and people of an identical age, who had no breast cancer. statistically significant differences in allostatic load biomarkers, such as systolic blood pressure, diastolic blood pressure, blood levels of triglycerides and glucose, and waist circumference were found between elderly patients with breast cancer and age controls (without breast cancer). The content of triglycerides in the blood of patients aged 60-74 years with breast cancer was 1.8 times higher than that in patients of the same age with no breast cancer (p<0.001). The blood glucose level was significantly higher in patients with breast cancer than in the age controls (5.8 ± 1.2 g/l versus 4.4 ± 1.1 g/l, p<0.01). Conclusion. The allostatic load and its variables should be used as biomarkers of increased risk of breast cancer.Рак молочной железы является ведущей формой новообразований среди женщин трудоспособного и пожилого возраста. Однако у пациенток с данной патологией недостаточно изучена аллостатическая нагрузка. Цель исследования – изучение аллостатической нагрузки у пациенток среднего и пожилого возраста с раком молочной железы. Материал и методы. Проведено обследование 65 пациенток среднего и 60 пациенток пожилого возраста с диагностированным гистологически раком молочной железы и 45 пациенток в возрасте 60–74 лет с отсутствием рака молочной железы. Аллостатическая нагрузка изучена в названных трех группах по уровню систолического и диастолического артериального давления, общего холестерина, триглицеридов, липопротеидов высокой и низкой плотности, глюкозы, альбуминов и величине окружности талии. Результаты. Установлена статистически значимо превышающая величина аллостатической нагрузки у пациенток пожилого возраста с раком молочной железы (4,3 ± 0,3 балла) по сравнению с пациентками среднего возраста с раком молочной железы (2,9 ± 0,2 балла) (p<0,01). Кроме того, величина аллостатической нагрузки у пациенток среднего возраста с диагностированным раком молочной железы достоверно выше (2,7 ± 0,2 балла), чем среди пациенток того же возраста без новообразования – 1,6 ± 0,1 балла. Аналогичная закономерность установлена и в группе пациенток пожилого возраста, среди которых показатель аллостатической нагрузки существенно выше у пациенток с наличием рака молочной железы (4,3 ± 0,3 балла), чем при его отсутствии – 2,9 ± 0,2 балла (р<0,001). Наиболее существенно пациентки 60–74 лет с раком молочной железы отличаются от возрастного контроля по таким показателям аллостатической нагрузки, как уровень общего холестерина – 5,8 ± 1,3 ммоль/л против 4,0 ± 0,8 ммоль/л, альбуминов 45,1 ± 7,4 % против 61,4 ± 7,6 % соответственно. Статистически значимые различия у пациенток пожилого возраста с раком молочной железы по сравнению с возрастным контролем (без рака молочной железы) выявлены также по таким биомаркерам аллостатической нагрузки, как систолическое артериальное давление, диастолическое артериальное давление, уровень в крови триглицеридов и глюкозы, окружность талии. Содержание триглицеридов в крови пациенток 60–74 лет с раком молочной железы в 1,8 раза выше, чем у пациенток аналогичного возраста с отсутствием новообразования (р<0,001). Уровень глюкозы в крови в сравниваемых группах пациенток достоверно выше у пациенток с раком молочной железы, он составляет 5,8 ± 1,2 г/л против 4,4 ± 1,1 г/л в возрастном контроле (р<0,01). Выводы. Аллостатическую нагрузку и ее показатели следует использовать в качестве биомаркеров повышенного риска развития рака молочной железы

The EC-Earth3 Earth system model for the Coupled Model Intercomparison Project 6

The Earth system model EC-Earth3 for contributions to CMIP6 is documented here, with its flexible coupling framework, major model configurations, a methodology for ensuring the simulations are comparable across different high-performance computing (HPC) systems, and with the physical performance of base configurations over the historical period. The variety of possible configurations and sub-models reflects the broad interests in the EC-Earth community. EC-Earth3 key performance metrics demonstrate physical behavior and biases well within the frame known from recent CMIP models. With improved physical and dynamic features, new Earth system model (ESM) components, community tools, and largely improved physical performance compared to the CMIP5 version, EC-Earth3 represents a clear step forward for the only European community ESM. We demonstrate here that EC-Earth3 is suited for a range of tasks in CMIP6 and beyond