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As the global temperature increases with changing climate, precipitation rates and patterns are affected through a wide range of physical mechanisms. The globally averaged intensity of extreme precipitation also changes [...]

The South Asian summer monsoon has been suggested to be influenced by atmospheric aerosols, and this influence can be the result of either local or remote emissions. We have used the Hadley Centre Global Environment Model Version 3 (HadGEM3) coupled atmosphere‐ocean climate model to investigate for the first time the centennial‐scale South Asian precipitation response to emissions of sulfur dioxide (SO2), the dominant anthropogenic precursor of sulfate aerosol, from different midlatitude regions. Despite the localized nature of the regional heating that results from removing SO2 emissions, all experiments featured a similar large‐scale precipitation response over South Asia, driven by ocean‐modulated changes in the net cross‐equatorial heat transport and an opposing cross‐equatorial northward moisture transport. The effects are linearly additive, with the sum of the responses from the experiments where SO2 is removed from the United States, Europe, and East Asia resembling the response seen in the experiment where emissions are removed from the northern midlatitudes as a whole, but with East Asia being the largest contributor, even per unit of emission or top‐of‐atmosphere radiative forcing. This stems from the fact that East Asian emissions can more easily influence regional land‐sea thermal contrasts and sea level pressure differences that drive the monsoon circulation, compared to emissions from more remote regions. Our results suggest that radiative effects of remote pollution should not be neglected when examining changes in South Asian climate and that and it is important to examine such effects in coupled ocean‐atmosphere modeling frameworks. Plain Language Summary: Atmospheric aerosols have been shown to exert a strong influence on global and regional climate through their radiative effects. The South Asian summer monsoon, a climate phenomenon on which billions of lives depend, has been suggested to be influenced by aerosols, and this influence can be the result of either local or remote emissions. We have used a global climate model to investigate how sensitive is the monsoon to emissions from remote industrialized regions such as Europe, the North America, and East Asia. Despite the localized nature of the regional heating that results from removing emissions in these regions, all of them featured a similar large‐scale rainfall change remotely over South Asia. This similarity reflects a common underlying mechanism, which involves a displacement of the tropical rain belt driven by aerosol effects on the temperature contrast between the two hemispheres of the Earth. We find that the effects of the different regions on South Asia are linearly additive, with East Asia being the largest contributor. This stems from the fact that its emissions can more easily influence regional land‐sea thermal contrasts and sea level pressure differences over Asia that drive the summer monsoon circulation, compared to emissions from more remote regions. Our results suggest that influences of remote pollution should not be neglected when examining changes in South Asian climate and can help inform policy on the cobenefits and side effects of ongoing strategies that control regional air pollution in extratropical regions. Key Points: Indian monsoon responses are qualitatively similar irrespective of the specific location of remote aerosol emissionsStill, East Asia is the strongest contributor to monsoon changes among remote regionsThe primary control of these responses is the large‐scale temperature gradient, with regional circulation features also modulating them [ABSTRACT FROM AUTHOR]

Future African aerosol emissions, and therefore air pollution levels and health outcomes, are uncertain and understudied. Understanding the future health impacts of pollutant emissions from this region is crucial. Here, this research gap is addressed by studying the range in the future health impacts of aerosol emissions from Africa in the Shared Socioeconomic Pathway (SSP) scenarios, using the UK Earth System Model version 1 (UKESM1), along with human health concentration-response functions. The effects of Africa following a high-pollution aerosol pathway are studied relative to a low-pollution control, with experiments varying aerosol emissions from industry and biomass burning. Using present-day demographics, annual deaths within Africa attributable to ambient particulate matter are estimated to be lower by 150 000 (5th-95th confidence interval of 67 000-234 000) under stronger African aerosol mitigation by 2090, while those attributable to O 3 are lower by 15 000 (5th-95th confidence interval of 9000-21 000). The particulate matter health benefits are realised predominantly within Africa, with the O 3 -driven benefits being more widespread - though still concentrated in Africa - due to the longer atmospheric lifetime of O 3 . These results demonstrate the important health co-benefits from future emission mitigation in Africa., Competing Interests: Competing interests. The contact author has declared that none of the authors has any competing interests.

This data descriptor reports the main scientific values from General Circulation Models (GCMs) in the Precipitation Driver and Response Model Intercomparison Project (PDRMIP). The purpose of the GCM simulations has been to enhance the scientific understanding of how changes in greenhouse gases, aerosols, and incoming solar radiation perturb the Earth's radiation balance and its climate response in terms of changes in temperature and precipitation. Here we provide global and annual mean results for a large set of coupled atmospheric-ocean GCM simulations and a description of how to easily extract files from the dataset. The simulations consist of single idealized perturbations to the climate system and have been shown to achieve important insight in complex climate simulations. We therefore expect this data set to be valuable and highly used to understand simulations from complex GCMs and Earth System Models for various phases of the Coupled Model Intercomparison Project., (© 2022. The Author(s).)

Atmospheric aerosols such as sulfate and black carbon (BC) generate inhomogeneous radiative forcing and can affect precipitation in distinct ways compared to greenhouse gases (GHGs). Their regional effects on the atmospheric energy budget and circulation can be important for understanding and predicting global and regional precipitation changes, which act on top of the background GHG-induced hydrological changes. Under the framework of the Precipitation Driver Response Model Inter-comparison Project (PDRMIP), multiple models were used for the first time to simulate the influence of regional (Asian and European) sulfate and BC forcing on global and regional precipitation. The results show that, as in the case of global aerosol forcing, the global fast precipitation response to regional aerosol forcing scales with global atmospheric absorption, and the slow precipitation response scales with global surface temperature response. Asian sulphate aerosols appear to be a stronger driver of global temperature and precipitation change compared to European aerosols, but when the responses are normalised by unit radiative forcing or by aerosol burden change, the picture reverses, with European aerosols being more efficient in driving global change. The global apparent hydrological sensitivities of these regional forcing experiments are again consistent with those for corresponding global aerosol forcings found in the literature. However, the regional responses and regional apparent hydrological sensitivities do not align with the corresponding global values. Through a holistic approach involving analysis of the energy budget combined with exploring changes in atmospheric dynamics, we provide a framework for explaining the global and regional precipitation responses to regional aerosol forcing.

Future projections of east Amazonian precipitation indicate drying, but they are uncertain and poorly understood. In this study we analyse the Amazonian precipitation response to individual atmospheric forcings using a number of global climate models. Black carbon is found to drive reduced precipitation over the Amazon due to temperature-driven circulation changes, but the magnitude is uncertain. CO 2 drives reductions in precipitation concentrated in the east, mainly due to a robustly negative, but highly variable in magnitude, fast response. We find that the physiological effect of CO 2 on plant stomata is the dominant driver of the fast response due to reduced latent heating, and also contributes to the large model spread. Using a simple model we show that CO 2 physiological effects dominate future multi-model mean precipitation projections over the Amazon. However, in individual models temperature-driven changes can be large, but due to little agreement, they largely cancel out in the model-mean.

We investigate the climate response to increased concentrations of black carbon (BC), as part of the Precipitation Driver Response Model Intercomparison Project (PDRMIP). A tenfold increase in BC is simulated by 9 global coupled-climate models, producing a model-median effective radiative forcing (ERF) of 0.82 (ranging from 0.41 to 2.91) Wm -2 , and a warming of 0.67 (0.16 to 1.66) K globally and 1.24 (0.26 to 4.31) K in the Arctic. A strong positive instantaneous radiative forcing (median of 2.10 Wm -2 based on five of the models) is countered by negative rapid adjustments (-0.64 Wm -2 for the same five models), which dampen the total surface temperature signal. Unlike other drivers of climate change, the response of temperature and cloud profiles to the BC forcing is dominated by rapid adjustments. Low-level cloud amounts increase for all models, while higher-level clouds are diminished. The rapid temperature response is particularly strong above 400 hPa, where increased atmospheric stabilization and reduced cloud cover contrast the response pattern of the other drivers. In conclusion, we find that this substantial increase in BC concentrations does have considerable impacts on important aspects of the climate system. However, some of these effects tend to offset one another, leaving a relatively small global warming of 0.47 K per Wm -2 - about 20 % lower than the response to a doubling of CO 2 . Translating the tenfold increase in BC to the present-day impact of anthropogenic BC (given the emissions used in this work) would leave a warming of merely 0.07 K.

Samples of size-fractionated particles were collected from local natural and anthropogenic sources in two industrial cities in the Yangtze River Delta, using either grab/resuspension sampling or ambient air sampling. The chemical characterizations of twenty one source profiles were obtained, based on elements (Al, As, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Pb and Zn), soluble ions (Cl - , NO 3 - , SO 4 2- , NH 4 + , K + , Na + and Ca 2+ ) and carbonaceous material such as organic carbon (OC) and elemental carbon (EC). The profiles vary between sources from different areas, as well as between different particulate sizes. Results show that particulate matter that originated as soil dust, construction dust and fugitive dust is typically rich in crustal elements, especially Al, Ca, Fe and Mg, while the presence of calcium is found to be a hallmark of the cement industry and ceramic industry. Dominant compositions of particles from coal-fired power plants are variable, with OC ranging from 2.2%-27%. Garbage-fired power plant and cooking smoke particulate emissions are enriched in Na, Cl - , OC and K due to the presence of salty and organic matter. The element Fe, ranging from 6.1% to 26.0%, is found to be an important marker for steel production dust. Vehicle exhaust profiles are characterized by high abundances of OC (12.1%-53.6%) and EC (3.9%-20.0%). Burning of straw results in K (1.6%-7.2%) and OC (12.4%-25.9%) being the dominant composition. Preliminary work has also been done on establishing local industrial profiles such as textile, ceramic and electroplating industries. This work could be used in receptor model studies to estimate the contributions of different sources to the size-fractionated particulate matter in the Yangtze River Delta., (Copyright © 2017 Elsevier B.V. All rights reserved.)

In this study, samples of size-fractionated particulate matter were collected continuously using a 9-size interval cascade impactor at an urban site in Nanjing, before, during and after the Asian Youth Games (AYG), from July to September of 2013, and the Youth Olympic Games (YOG), from July to September of 2014. First, elemental concentrations, water-soluble ions including Cl - , NO 3 - , SO 4 2- , NH 4 + , K + concentrations were 90.4±20.0μg/m + during the 2013 AYG and 70.6±25.3μg/m 2+ , organic carbon (OC) and elemental carbon (EC) were analysed. Then, the source apportionment of the fine and coarse particulate matter was carried out using the chemical mass balance (CMB) model. The average PM 10 the average concentrations were 50.0±12.8μg/m 3 in 2013 and 34.6±17.0μg/m 3 during the 2014 YOG. For PM 2.1, the average concentrations were 50.0±12.8μg/m 3 in 2013 and 34.6±17.0μg/m 3 in 2014. Investigations showed that the average concentrations of particles declined significantly from 2013 to 2014, and concentrations were at the lowest levels during the events. Results indicated that OC, EC, sulfate and crustal elements have significant monthly and size-based variations. The major components, including crustal elements, water-soluble ions and carbonaceous aerosol accounted for 75.3-91.9% of the total particulate mass concentrations during the sampling periods. Fugitive dust, coal combustion dust, iron dust, construction dust, soil dust, vehicle exhaust, secondary aerosols and sea salt have been classified as the main emissions in Nanjing. The source apportionment results indicate that the emissions from fugitive dust, which was the most abundance emission source during the 2013 AYG, contributed to 23.0% of the total particle mass. However, fugitive dust decreased to 6.2% of the total particle mass during the 2014 YOG. Construction dust (14.7% versus 7.8% for the AYG and the YOG, respectively) and secondary sulfate aerosol (9.3% versus 8.0% for the AYG and the YOG, respectively) showed the same trend as fugitive dust, suggesting that the mitigation measures of controlling particles from the paved roads, construction and industry worked more efficiently during the YOG., (Copyright © 2016 Elsevier B.V. All rights reserved.)