Journal ArticleDOI
Flood or drought: How do aerosols affect precipitation?
Daniel Rosenfeld,Ulrike Lohmann,Graciela B. Raga,Colin D. O'Dowd,Markku Kulmala,Sandro Fuzzi,Anni Reissell,Meinrat O. Andreae +7 more
TLDR
A conceptual model is proposed that explains this apparent dichotomy of pristine tropical clouds with low CCN concentrations rain out too quickly to mature into long-lived clouds and heavily polluted clouds evaporate much of their water before precipitation can occur.Abstract:
Aerosols serve as cloud condensation nuclei (CCN) and thus have a substantial effect on cloud properties and the initiation of precipitation. Large concentrations of human-made aerosols have been reported to both decrease and increase rainfall as a result of their radiative and CCN activities. At one extreme, pristine tropical clouds with low CCN concentrations rain out too quickly to mature into long-lived clouds. On the other hand, heavily polluted clouds evaporate much of their water before precipitation can occur, if they can form at all given the reduced surface heating resulting from the aerosol haze layer. We propose a conceptual model that explains this apparent dichotomy.read more
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A numerical study of the effect of different aerosol types on East Asian summer clouds and precipitation
TL;DR: In this paper, the authors investigated the anthropogenic aerosol impact on the summer monsoon clouds and precipitation in East Asia using the NCAR Community Atmospheric Model version 5 (CAM5), a state-of-the-art climate model considering aerosol direct, semi-direct and indirect effects.
Journal ArticleDOI
The environment of precipitating shallow cumulus convection
TL;DR: In this paper, the authors derived estimates of precipitation in a typical undisturbed trade wind region from 2 months of radar reflectivity data and compared to the meteorological environment determined from soundings, surface flux, and airborne-lidar data.
Journal ArticleDOI
Seasonal variation of CCN concentrations and aerosol activation properties in boreal forest
S.-L. Sihto,Jyri Mikkilä,Joonas Vanhanen,Mikael Ehn,Li Liao,Katrianne Lehtipalo,Pasi Aalto,Jonathan Duplissy,Jonathan Duplissy,Tuukka Petäjä,Veli-Matti Kerminen,Veli-Matti Kerminen,Michael Boy,Markku Kulmala +13 more
TL;DR: In this paper, the annual cycle of cloud condensation nuclei (CCN) concentrations and critical diameter for cloud droplet activation as a function of supersaturation were measured using a CCN counter and a HTDMA (hygroscopicity tandem differential mobility analyzer) at SMEAR II station, Hyytiala, Finland.
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Chemical characteristics of PM2.5 at a source region of biomass burning emissions: Evidence for secondary aerosol formation
TL;DR: The scattering species (SO4(2-) + NO3(-) + OC) contribute ~50% to PM2.5 mass during October-March whereas absorbing species (EC) contribute only ~4% in October-February and subsequently increases to ~10% in March, indicating significance of these species in regional radiative forcing.
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Microphysical Processes Evident in Aerosol Forcing of Tropical Deep Convective Clouds
TL;DR: In this paper, the effects of aerosols on tropical deep convective clouds (DCCs) were investigated in a series of large-scale, two-dimensional cloud-resolving model simulations.
References
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TL;DR: PfPMP1)与感染红细胞、树突状组胞以及胎盘的单个或多个受体作用,在黏附及免疫逃避中起关键的作�ly.
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Aerosols, climate, and the hydrological cycle
TL;DR: Human activities are releasing tiny particles (aerosols) into the atmosphere that enhance scattering and absorption of solar radiation, which can lead to a weaker hydrological cycle, which connects directly to availability and quality of fresh water, a major environmental issue of the 21st century.
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Global indirect aerosol effects: a review
Ulrike Lohmann,Johann Feichter +1 more
TL;DR: In this article, the effects of aerosols on the climate system are discussed and different approaches how the climatic implications of these effects can be estimated globally as well as improvements that are needed in global climate models in order to better represent indirect aerosol effects are discussed.
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Climate Effects of Black Carbon Aerosols in China and India
TL;DR: A global climate model used to investigate possible aerosol contributions to trends in China and India found precipitation and temperature changes in the model that were comparable to those observed if the aerosols included a large proportion of absorbing black carbon (“soot”), similar to observed amounts.
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Inaugural Article by a Recently Elected Academy Member
Jian Xu,Jeffrey I. Gordon +1 more