| Aerosol is the main pollutant in the atmosphere.It interacts with the solar short wave radiation or the surface long wave infrared radiation directly because it can change the intensity and the transmission direction of light by scattering or absorption.And it is also the cloud condensation nuclei,so it affects solar short wave radiation and surface long wave infrared radiation transmission indirectly by affecting the cloud formation,cloud life cycle and cloud albedo,etc.Aerosol is one of the most important factors that disturbs the radiation balance of the earth atmosphere system,so in-depth understanding of the changes in aerosol optical properties and radiative effects is of great significance for understanding current aerosol pollution status and climatic effects,as well as predicting global climate change under the future aerosol emission status.At present,the uncertainty of aerosol radiative forcing is great.Lack of understanding in aerosol optical properties,type distribution,radiative effects and their interaction mechanism is an important reason for this uncertainty.There are currently few AERONET sites in China,especially in the Northeast China,which severely limits the studies on the aerosol optical properties and radiative effects in Northeast China.In addition,there are many shortcomings in the current related research.Therefore,it is necessary to fully understand the aerosol optical properties and radiative effects in Harbin and the regional environmental changes caused by aerosols in high-pollution haze events,which is of great significance to understand the local aerosol pollution status and the regional or global climate changes.The aerosol optical properties of the Harbin from 2017 to 2018 in the past two years were calculated and retrieved based on the self-built aerosol ground observation platform and the corresponding Skyrad inversion algorithm.The monthly,seasonal and frequency distribution of aerosol optical properties,such as AOD,AE and SSA,were studied in detail.On the basis of aerosol ground observation,four commonly used aerosol optical identification models,such as AOD-AE,AOD-AROD,AE-SSA and AE-AAE,were used to identify aerosol types.The performance of different identification models were analysised.Finally,the aerosol type distribution in urban Harbin was obtained and analyzed under the synergy of various models.The radiative forcing in the top of the atmosphere,at the surface and within the atmosphere in Harbin from 2017 to 2018 was simulated and calculated based on the SBDART discrete coordinate radiative transmission model.The radiative effects of aerosols in different atmospheric positions and their monthly,seasonal and frequency distribution were analyzed.Based on the research of aerosol optical properties and type identification,the influence of aerosol optical properties on the changes of radiative forcing and the contribution of different types of aerosol to the seasonal distribution of aerosol radiative forcing were further analyzed.The meteorological elements,main polluted particles,main reactive gases,aerosol optical properties,dominant aerosol types and aerosol radiative effects were comprehensively studied with the collaborative use of ground-based remote sensing,satellite remote sensing and meteorological station observation during a typical heavy pollution haze event in Harbin during October 18 to 20,2017.The causes,aerosol optical properties,dominant types and the aerosol radiative forcing of this haze events were analyzed in detail.Study on aerosol optical properties and direct radiative effects in Harbin will help to make up for the deficiencies of existing related studies in Northeast China and will also improve our understanding of local aerosol pollution status and climate effects.At the same time,it will further enrich the data of aerosol ground based observation and radiative forcing simulation in Northeast China,which is of great theoretical significance and application value for the assessment of climate change caused by aerosol and the prediction of regional or global climate change under the future aerosol emission status. |
