Aerosol impacts on radiative and microphysical properties of clouds and precipitation formation

Alizadeh, Omid; Gharaylou, Maryam

doi:10.1016/j.atmosres.2016.10.021

Cited by 60 publications

(22 citation statements)

References 64 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Some other large‐scale atmospheric or boundary conditions may also have contributed to the diurnal asymmetry in the change of soil surface temperature. Considering that changes in aerosol loading have little effect on the longwave radiation of clouds (Alizadeh‐Choobari & Gharaylou, ) and aerosol emissions slowed after the mid‐1990s in China (Qin et al, ; Streets et al, ), aerosols could not be a factor in the rapid increase of ST 0min after 1998. Furthermore, as China's black carbon emissions reached their highest point in the mid‐1990s (Wang et al, ), they may have enhanced ST 0min through reduced heat loss from the Earth's surface in earlier years but cannot be the cause for the rapid increase of ST 0min after 1998.…”

Section: Implications Of the Divergences Between Soil And Air Temperamentioning

confidence: 99%

Maximum and Minimum Soil Surface Temperature Trends Over China, 1965–2014

et al. 2018

View full text Add to dashboard Cite

Minimum and maximum soil surface temperatures have shown significant warming trends since the midtwentieth century in China, with minimum temperatures rising at a faster pace than maximums, resulting in a decrease in the soil surface diurnal temperature range. Similar to air temperature, these changes demonstrate spatial coherence, with regions at higher latitudes experiencing relatively more change. While increases in air temperatures in China slowed after 1998, paralleling the global “warming hiatus,” soil temperatures at the surface and in shallow layers have continued to rise across China. The increases in soil surface temperatures are fastest at night since 1998, reducing the soil surface diurnal temperature range. Thus, we find that while the decrease in the diurnal air temperature range mainly happened during the earlier “dimming” period ending around 1988, the decrease in the diurnal soil surface temperature range is detectable only during the renewed dimming period after 1998. This has caused soil temperatures at the surface and in shallow layers to diverge from air temperatures since 1998. Although changes in soil temperatures were associated with changes in air temperature, the patterns of change are different. Calculations using only nonurban stations show similar warming rates, indicating that the effects of urbanization are small.

show abstract

Section: Implications Of the Divergences Between Soil And Air Temperamentioning

confidence: 99%

Maximum and Minimum Soil Surface Temperature Trends Over China, 1965–2014

et al. 2018

View full text Add to dashboard Cite

show abstract

“…This rather drastic change in the relative frequency of precipitation intensity implies that the underlying cloud microphysics experiences significant changes if the aerosol loading increases in the range N 0 = 800-12,800 cm −3 . Many studies have reported a larger proportion of heavy rain rate in polluted conditions [24,29,59]. In particular, Chen et al [59] reported that the frequency of heavy rain rate increases monotonically with increasing aerosol loading.…”

Section: Atmosphere 2018 8 Of 23mentioning

confidence: 99%

“…Several studies have shown non-monotonic relationships between the aerosol number concentration and precipitation from deep convective clouds [7,8,10,29,30]. The increases in precipitation amounts due to heavier aerosol loading are mainly explained by the reinforcement of convection and ice microphysical processes in the clouds.…”

Section: Introductionmentioning

confidence: 99%

“…According to the analyses by Connolly et al [31], the main cause of the suppressed precipitation in response to heavy aerosol loading is the weakened storm intensity under polluted conditions. Alizadeh-Choobari and Gharaylou [29] used a two-moment bulk microphysics scheme to simulate deep convective clouds over the northwestern region of Iran, showing non-monotonic trends in precipitation amounts with respect to aerosol loading, but the analyses were mostly devoted to changes in precipitation rates.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Non-Monotonic Dependencies of Cloud Microphysics and Precipitation on Aerosol Loading in Deep Convective Clouds: A Case Study Using the WRF Model with Bin Microphysics

et al. 2018

View full text Add to dashboard Cite

Aerosol-cloud-precipitation interactions in deep convective clouds are investigated through numerical simulations of a heavy precipitation event over South Korea on 15–16 July 2017. The Weather Research and Forecasting model with a bin microphysics scheme is used, and various aerosol number concentrations in the range N0 = 50–12,800 cm−3 are considered. Precipitation amount changes non-monotonically with increasing aerosol loading, with a maximum near a moderate aerosol loading (N0 = 800 cm−3). Up to this optimal value, an increase in aerosol number concentration results in a greater quantity of small droplets formed by nucleation, increasing the number of ice crystals. Ice crystals grow into snow particles through deposition and riming, leading to enhanced melting and precipitation. Beyond the optimal value, a greater aerosol loading enhances generation of ice crystals while the overall growth of ice hydrometeors through deposition stagnates. Subsequently, the riming rate decreases because of the smaller size of snow particles and supercooled drops, leading to a decrease in ice melting and a slight suppression of precipitation. As aerosol loading increases, cold pool and low-level convergence strengthen monotonically, but cloud development is more strongly affected by latent heating and convection within the system that is non-monotonically reinforced.

show abstract

“…By modifying the number concentration and size of cloud droplets (Twomey, 1974;Andreae et al, 2004), as well as thermodynamic (Koren et al, 2005) and dynamic effects (Khain, 2009), aerosols have intricate effects on radiative (Fan et al, 2013), microphysical and macrophysical properties of clouds (Andreae et al, 2004;Fan et al, 2013), and precipitation formation (Khain, 2009;Alizadeh-Choobari and Gharaylou, 2017), all of which have significant implications on the climate system. These so-called aerosol indirect effects have a long history in the literature, yet they have remained mostly uncertain and controversial in climate studies (Carslaw et al, 2013), making it difficult to understand robustly the future climate.…”

mentioning

confidence: 99%

Impact of aerosol number concentration on precipitation under different precipitation rates

Alizadeh

2018

Meteorological Applications

Self Cite

View full text Add to dashboard Cite

Mainly by modifying the number concentration and size of cloud droplets, the dynamic and thermodynamic effects of aerosols are important in the formation of precipitation, but so far different and occasionally opposite responses of precipitation to aerosol concentration have been noted. By conducting two numerical experiments with different aerosol concentrations, the impact of aerosol number concentration on precipitation under different precipitation rates is examined. To this end, the Weather Research and Forecasting (WRF) model with a two‐moment aerosol‐aware bulk microphysical scheme was applied. Results indicate that mainly through redistribution of precipitation both spatially and temporarily, more hygroscopic aerosols in the atmosphere could potentially reduce light precipitation events, but increase heavy precipitation events. In regions with a high precipitation rate (> 1 mm/hr), an ample influx of water vapour exists. Thus, cloud droplets have no need to compete for water vapour in order to grow, which results in an enhancement of precipitation under the polluted atmosphere. On the other hand, less efficient autoconversion processes and/or increased cloud‐top evaporation may contribute to the decrease in light (< 0.6 mm/hr) to moderate (0.6–1 mm/hr) precipitation under the polluted atmosphere. A delay in the onset of precipitation is identified in the polluted experiment, which leads to a significant increase in precipitation rate, primarily due to more freezing of cloud droplets and extra release of latent heat of freezing, which invigorates cloud developments, while intensification of secondary clouds by aerosols might have also partly contributed.

show abstract

Aerosol impacts on radiative and microphysical properties of clouds and precipitation formation

Cited by 60 publications

References 64 publications

Maximum and Minimum Soil Surface Temperature Trends Over China, 1965–2014

Maximum and Minimum Soil Surface Temperature Trends Over China, 1965–2014

Non-Monotonic Dependencies of Cloud Microphysics and Precipitation on Aerosol Loading in Deep Convective Clouds: A Case Study Using the WRF Model with Bin Microphysics

Impact of aerosol number concentration on precipitation under different precipitation rates

Contact Info

Product

Resources

About