scholarly journals Toward reconciling the influence of atmospheric aerosols and greenhouse gases on light precipitation changes in Eastern China

2016 ◽  
Vol 121 (10) ◽  
pp. 5878-5887 ◽  
Author(s):  
Yuan Wang ◽  
Po-Lun Ma ◽  
Jonathan H. Jiang ◽  
Hui Su ◽  
Philip J. Rasch
2021 ◽  
pp. 1-13
Author(s):  
Kehan Li

Climate change is of great importance in modern times and global warming is considered as a significant part of climate change. It is proved that human’s emissions such as greenhouse gases are one of the main sources of global warming (IPCC, 2018). Apart from greenhouse gases, there is another kind of matter being released in quantity via emissions from industries and transportations and playing an important role in global warming, which is aerosol. However, atmospheric aerosols have the net effect of cooling towards global warming. In this paper, climate change with respect to global warming is briefly introduced and the role of aerosols in the atmosphere is emphasized. Besides, properties of aerosols including dynamics and thermodynamics of aerosols as well as interactions with solar radiation are concluded. In the end, environmental policies and solutions are discussed. Keywords: Climate change, Global warming, Atmospheric aerosols, Particulate matter, Radiation, Environmental policy.


2020 ◽  
Vol 33 (13) ◽  
pp. 5357-5369
Author(s):  
Chunhui Lu ◽  
Fraser C. Lott ◽  
Ying Sun ◽  
Peter A. Stott ◽  
Nikolaos Christidis

AbstractIn China, summer precipitation contributes a major part of the total precipitation amount in a year and has major impacts on society and human life. Whether any changes in summer precipitation are affected by external forcing on the climate system is an important issue. In this study, an optimal fingerprinting method was used to compare the observed changes of total, heavy, moderate, and light precipitation in summer derived from newly homogenized observation data with the simulations from multiple climate models participating in phase 5 of the Coupled Model Intercomparison Project (CMIP5). The results demonstrate that the anthropogenic forcing signal can be detected and separated from the natural forcing signal in the observed increase of seasonal accumulated precipitation amount for heavy precipitation in summer in China and eastern China (EC). The simulated changes in heavy precipitation are generally consistent with observed change in China but are underestimated in EC. When the changes in precipitation of different intensities are considered simultaneously, the human influence on simultaneous changes in moderate and light precipitation can be detected in China and EC in summer. Changes attributable to anthropogenic forcing explain most of the observed regional changes for all categories of summer precipitation, and natural forcing contributes little. In the future, with increasing anthropogenic influence, the attribution-constrained projection suggests that heavy precipitation in summer will increase more than that from the model raw outputs. Society may therefore face a higher risk of heavy precipitation in the future.


2017 ◽  
Author(s):  
Pei Hou ◽  
Shiliang Wu ◽  
Jessica L. McCarty

Abstract. Wet deposition driven by precipitation is an important sink for atmospheric aerosols and soluble gases. We investigate the sensitivity of atmospheric aerosol lifetimes to precipitation intensity and frequency in the context of global climate change. Our study, based on the GEOS-Chem model simulation, shows that the removal efficiency and hence the atmospheric lifetime of aerosols have significantly higher sensitivities to precipitation frequencies than to precipitation intensities, indicating that the same amount of precipitation may lead to different removal efficiencies of atmospheric aerosols. Combining the long-term trends of precipitation patterns for various regions with the sensitivities of atmospheric aerosols lifetimes to various precipitation characteristics allows us to examine the potential impacts of precipitation changes on atmospheric aerosols. Analyses based on an observational dataset show that precipitation frequency in some regions have decreased in the past 14 years, which might increase the atmospheric aerosol lifetimes in those regions. Similar analyses based on multiple reanalysis meteorological datasets indicate that the precipitation changes over the past 30 years can lead to perturbations in the atmospheric aerosol lifetimes by 10 % or higher at the regional scale.


Atmosphere ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 210
Author(s):  
Kefan Chen ◽  
Liang Ning ◽  
Zhengyu Liu ◽  
Jian Liu ◽  
Weiyi Sun ◽  
...  

In this study, the influences on persistent droughts over Eastern China from tropical volcanic eruptions with three categories of magnitudes, i.e., 25 Tg, 50 Tg, and 100 Tg, were investigated through three groups of volcanic sensitivity experiments based on the Community Earth System Model (CESM). The results showed that, the 25 Tg tropical volcanic eruptions are too weak to significantly influence the regional precipitation changes over Eastern China, while the 50 Tg tropical volcanic eruptions can strongly intensify droughts and prolong the drought conditions for about five years. Both the extension and intensification of the drought conditions induced by 100 Tg tropical volcanic eruption are the largest among the three sensitivity experiments. These drought conditions are mainly caused by the weakened East Asia Summer Monsoon (EASM), and their extension and intensification depend on the strength of the volcanic eruptions. The intensities of weakened EASMs after volcanic eruptions are associated with the distinct ocean–land thermal contrast after eruptions. The ocean–land thermal contrast is the largest after the 100 Tg tropical volcanic eruptions, while it is much weaker after the 25 Tg volcanic eruptions. The durations of drought extensions are determined by the recovery rates of the West Pacific Subtropical High (WPSH), which are associated with the magnitudes of the volcanic eruptions.


Author(s):  
Meinrat O Andreae

Looked at in a simplistic way, aerosols have counteracted the warming effects of greenhouse gases (GHG) over the past century. This has not only provided some ‘climate protection’, but also prevented the true magnitude of the problem from becoming evident. In particular, it may have resulted in an underestimation of the sensitivity of the climate system to the effect of GHG. Over the present century, the role of aerosols in opposing global warming will wane, as there are powerful policy reasons to reduce their emissions and their atmospheric lifetimes are short in contrast to those of the GHG. On the other hand, aerosols will continue to play a role in regional climate change, especially with regard to the water cycle. The end of significant climate protection by atmospheric aerosols, combined with the potentially very high sensitivity of the climate system, makes sharp and prompt reductions in greenhouse gas emissions, especially CO 2 , very urgent.


2019 ◽  
Vol 226 ◽  
pp. 240-254 ◽  
Author(s):  
Yuqing Zhang ◽  
Chuanming Liu ◽  
Qinglong You ◽  
Changchun Chen ◽  
Wenxin Xie ◽  
...  

Author(s):  
Paul I. Palmer

Earth’s atmosphere is tied closely with the Sun. The Sun emits electromagnetic radiation at a wide range of wavelengths. Radiation is transported through the atmosphere by transmission, absorption, and scattering. ‘Atmospheric physics’ outlines the Earth’s radiation budget—the incoming and outgoing radiation, equilibrium between them, and departures from this equilibrium due to increasing levels of clouds, greenhouse gases, and atmospheric aerosols. It then describes the greenhouse gases that absorb and emit radiation and the thermodynamics of the atmosphere. The importance of water, the dominant atmospheric constituent responsible for the loss of radiative energy to space and hence atmospheric cooling, and the electrical energy stored in the atmosphere are also discussed.


2018 ◽  
Vol 18 (11) ◽  
pp. 8173-8182 ◽  
Author(s):  
Pei Hou ◽  
Shiliang Wu ◽  
Jessica L. McCarty ◽  
Yang Gao

Abstract. Wet deposition driven by precipitation is an important sink for atmospheric aerosols and soluble gases. We investigate the sensitivity of atmospheric aerosol lifetimes to precipitation intensity and frequency in the context of global climate change. Our sensitivity model simulations, through some simplified perturbations to precipitation in the GEOS-Chem model, show that the removal efficiency and hence the atmospheric lifetime of aerosols have significantly higher sensitivities to precipitation frequencies than to precipitation intensities, indicating that the same amount of precipitation may lead to different removal efficiencies of atmospheric aerosols. Combining the long-term trends of precipitation patterns for various regions with the sensitivities of atmospheric aerosol lifetimes to various precipitation characteristics allows us to examine the potential impacts of precipitation changes on atmospheric aerosols. Analyses based on an observational dataset show that precipitation frequencies in some regions have decreased in the past 14 years, which might increase the atmospheric aerosol lifetimes in those regions. Similar analyses based on multiple reanalysis meteorological datasets indicate that the changes of precipitation intensity and frequency over the past 30 years can lead to perturbations in the atmospheric aerosol lifetimes by 10 % or higher at the regional scale.


2016 ◽  
Author(s):  
Tianyi Fan ◽  
Xiaohong Liu ◽  
Po-Lun Ma ◽  
Qiang Zhang ◽  
Zhanqing Li ◽  
...  

Abstract. Emissions of aerosols and gas precursors in China have increased significantly over the past three decades with the rapid economic growth. These increases might have a large climate effect. However, global aerosol-climate models often show large biases in aerosol distribution and radiative forcing in China, and these biases are often attributed to uncertainties and biases associated with the emission inventory used to drive the models. In this study, an energy-statics and technology-based emission inventory, Multi-scale Emission Inventory for China (MEIC), was compiled and used to drive the Community Atmosphere Model Version 5 (CAM5) to evaluate aerosol distribution and radiative effects in China against observations, compared with the model simulations with the widely-used IPCC AR5 emission inventory. We found that the new MEIC emission improves the annual mean AOD simulations in eastern China by 12.9 % compared with MODIS observations and 14.7 % compared with MISR observations, and explains 22 %–28 % of the AOD low bias simulated with the AR5 emission. Seasonal variation of the MEIC emission leads to a better agreement with the observed surface concentrations of primary aerosols (i.e., primary organic carbon and black carbon) than the AR5 emission, while the seasonal variation of secondary aerosols (i.e., sulfate and secondary organic aerosol) depends less on the emission. The new emission inventory estimates the annual averaged aerosol direct radiative effect at TOA, surface, and atmosphere to be −0.50, −12.76, and 12.26 W m−2 respectively over eastern China, which are enhanced by −0.19, −2.42, and 2.23 W m−2 compared with the AR5 emission. Due to higher winter BC emission in MEIC, the atmospheric warming effect and the surface cooling of BC are twice as much as those using the AR5 emission. This study highlights the importance of improving the aerosol and gas precursor emissions in modeling the atmospheric aerosols and their radiative effects.


2017 ◽  
Vol 30 (4) ◽  
pp. 1381-1396 ◽  
Author(s):  
Shuangmei Ma ◽  
Tianjun Zhou ◽  
Dáithí A. Stone ◽  
Debbie Polson ◽  
Aiguo Dai ◽  
...  

Abstract Changes in precipitation characteristics directly affect society through their impacts on drought and floods, hydro-dams, and urban drainage systems. Global warming increases the water holding capacity of the atmosphere and thus the risk of heavy precipitation. Here, daily precipitation records from over 700 Chinese stations from 1956 to 2005 are analyzed. The results show a significant shift from light to heavy precipitation over eastern China. An optimal fingerprinting analysis of simulations from 11 climate models driven by different combinations of historical anthropogenic (greenhouse gases, aerosols, land use, and ozone) and natural (volcanic and solar) forcings indicates that anthropogenic forcing on climate, including increases in greenhouse gases (GHGs), has had a detectable contribution to the observed shift toward heavy precipitation. Some evidence is found that anthropogenic aerosols (AAs) partially offset the effect of the GHG forcing, resulting in a weaker shift toward heavy precipitation in simulations that include the AA forcing than in simulations with only the GHG forcing. In addition to the thermodynamic mechanism, strengthened water vapor transport from the adjacent oceans and by midlatitude westerlies, resulting mainly from GHG-induced warming, also favors heavy precipitation over eastern China. Further GHG-induced warming is predicted to lead to an increasing shift toward heavy precipitation, leading to increased urban flooding and posing a significant challenge for mega-cities in China in the coming decades. Future reductions in AA emissions resulting from air pollution controls could exacerbate this tendency toward heavier precipitation.


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