Analysis of Long-Term Aerosol Optical Properties Combining AERONET Sunphotometer and Satellite-Based Observations in Hong Kong

Abstract

This study analyzes seasonal characteristics and long-term variations in aerosol optical parameters in Hong Kong from 2006 to 2021 using AERONET data and satellite-based observations based on the extreme-point symmetric mode decomposition (ESMD) model. The dominant aerosol types in Hong Kong are mixed aerosols and urban/industrial aerosols with fine-mode sizes, and slightly absorbing or non-absorbing properties. Aerosol optical depth (AOD), Angstrom exponent (AE) and single scattering albedo (SSA) varied seasonally with a lower AOD but higher AE and SSA in summer, and elevated AOD but lower AE and SSA in spring and winter. The long-term variations show the year 2012 to be a turning point, with an upward trend in AOD and AE before 2012 and then downwards after 2012. However, for SSA, a rising trend was exhibited in both pre- and post-2012 periods, but with a larger gradient in the first period. The ESMD analysis shows shorter-term, non-linear fluctuations in aerosol optical parameters, with alternating increasing and declining trends. The examination of the relationships between AOD and meteorological factors based on the extreme gradient boosting (XGBoost) method shows that the effects of weather conditions on AOD are complex and non-monotonic. A lower relative humidity, higher wind speed in southwest directions and lower temperature are beneficial to the abatement of aerosol loads in Hong Kong. In conclusion, the findings of this study enhance the understanding of aerosol properties and the interactions between aerosol loading and meteorological factors.

Effects of aerosol particles on precipitation and cloud parameters over East Africa-Ethiopia using MODIS satellite data: Part 01

“…Those results are similar to the findings and the reasons in the study from eastern China (Liu et al, 2021). The seasonal results for the parameters were similar to those of the observations made in Austria (Yang et al, 2021), Algeria (Khan et al, 2021), eastern China (Liu et al, 2021), and Hong Kong (Yu et al, 2022), despite the fact that there had been no prior studies on the sites in the clustered regions. The discrepancies we discovered were in the minimums with different data periods and site selections.…”

“…The discrepancies we discovered were in the minimums with different data periods and site selections. Furthermore, in the study conducted by Yu et al (2022) the minimum values were primarily at bega and the maximum at kiremt.…”

Assessing Lidar Ratio Impact on CALIPSO Retrievals Utilized for the Estimation of Aerosol SW Radiative Effects across North Africa, the Middle East, and Europe

“…The aforementioned factors, particularly those related to aerosol properties, govern at a large degree aerosol-radiation interactions, thus highlighting the importance of a reliable and accurate aerosol typing. Ground-based measurements, acquired using instrumentations deploying passive or active remote sensing techniques, have provided critical insight on aerosol-speciated intensive and extensive radiative properties [18][19][20][21][22][23]. Spaceborne observations, providing near-global coverage, have effectively overcome the spatial constraints of ground-based stations [24][25][26][27][28][29][30].…”

Variation of Aerosol Optical Properties over Cluj-Napoca, Romania, Based on 10 Years of AERONET Data and MODIS MAIAC AOD Product

“…In Asia, Tu et al (2021) used AERONET data to determine aerosol characteristics over four observation sites in East China, highlighting the frequency of urban pollution from fossil fuel burning during a period of 20 years [9]. Yu et al (2022), determined the dominant aerosol types in Hong Kong and their interactions with meteorological factors by using both AERONET data and satellite-based observations from 2006 to 2021 [10]. Natural, largescale events of aerosol intrusions have been researched by Sun et al (2022), who studied two extreme dust events over North China in March, 2021, by using AERONET in situ observations and CALIPSO satellite data to obtain the distribution characteristics of dust aerosol optical properties along their transport pathways [11].…”