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Long-term trends of aerosol and cloud fraction over Eastern China based on ground-based observations
Abstract We looked into the long-term variability of aerosols and clouds over Eastern China (EC) using MICAPS ground-based data from 1995 to 2019 and MODIS aerosol optical depth (AOD) retrieval from 2003 to 2019. The ground-based observed visibility (VIS) was used to characterize aerosol concentrations. Our study indicate that VIS shows a significant shift over EC in recent decades, as evidenced by falling (P1: 1995–2006)-flat (P2: 2007–2013)-rising (P3: 2014–2019) periods. Correspondingly, a change was observed in cloud fraction (CF) from a strong increase to a slow fluctuation during the three periods over the Beijing-Tianjin-Hebei (BTH), but no significant variation over the Yangtze River Delta (YRD) region. In addition, the CF-VIS shows a negative correlation during both P1 and P3 periods while this relationship weakened during P3 (35% weaker in BTH and 44% weaker in YRD). However, it is important to note that this weakening may be influenced by a few factors, such as data processing methods, the location of aerosols relative to the cloud, relative humidity (RH), and large-scale circulation etc. Further studies, including numerical simulations and analysis, are required to determine how much change of cloudiness is attributed to aerosols.
Highlights Cloud fraction (CF) has changed from strong to slow growth during the rising and declining aerosol periods1995–2019) over BTH. Aerosol concentrations, characterized by visibility (VIS), have been negatively correlated with CF during the study period. The negative correlation between VIS and CF has weakened during the declining period of aerosol emissions in recent years.
Long-term trends of aerosol and cloud fraction over Eastern China based on ground-based observations
Abstract We looked into the long-term variability of aerosols and clouds over Eastern China (EC) using MICAPS ground-based data from 1995 to 2019 and MODIS aerosol optical depth (AOD) retrieval from 2003 to 2019. The ground-based observed visibility (VIS) was used to characterize aerosol concentrations. Our study indicate that VIS shows a significant shift over EC in recent decades, as evidenced by falling (P1: 1995–2006)-flat (P2: 2007–2013)-rising (P3: 2014–2019) periods. Correspondingly, a change was observed in cloud fraction (CF) from a strong increase to a slow fluctuation during the three periods over the Beijing-Tianjin-Hebei (BTH), but no significant variation over the Yangtze River Delta (YRD) region. In addition, the CF-VIS shows a negative correlation during both P1 and P3 periods while this relationship weakened during P3 (35% weaker in BTH and 44% weaker in YRD). However, it is important to note that this weakening may be influenced by a few factors, such as data processing methods, the location of aerosols relative to the cloud, relative humidity (RH), and large-scale circulation etc. Further studies, including numerical simulations and analysis, are required to determine how much change of cloudiness is attributed to aerosols.
Highlights Cloud fraction (CF) has changed from strong to slow growth during the rising and declining aerosol periods1995–2019) over BTH. Aerosol concentrations, characterized by visibility (VIS), have been negatively correlated with CF during the study period. The negative correlation between VIS and CF has weakened during the declining period of aerosol emissions in recent years.
Long-term trends of aerosol and cloud fraction over Eastern China based on ground-based observations
Yang, Tong (Autor:in) / Ma, Xiaoyan (Autor:in) / Zhao, Jianqi (Autor:in)
Atmospheric Environment ; 309
10.07.2023
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch