Optical properties and effects on direct solar irradiance of aerosols: Asian East case

Atmospheric aerosol is an important factor that affects solar irradiance. In this study, we examined the total atmospheric optical depth, aerosol optical depth AOD and the vertical particle size distribution in East Asia in terms of aerosol type during three years. The temporal variation of the aerosol optical depth for each site showed a constant mode renewed each year, the large AOD0,5 are recorded in spring and summer in an almost periodic manner, with maximums around 0.95 in Seoul, 0.08 in Chiang Mai and 1.34 in EPA-NCU. The particle size distributions under a bimodal lognormal form present a remarkable increase in volume concentration of fine and coarse modes during spring. The aerosols reduce solar irradiance by 37.33 ± 0.78% in Chiang Mai, 33.48 ± 6.43% in EPA-NCU and 38.59 ± 3.86% in Seoul

Effect of the main active volcanoes on aerosol optical properties

Processing of the measurements obtained by the AERONET network of the optical parameters characteristic of the atmospheric aerosol carried out makes it possible to compare the optical effects of 2020 volcanic eruptions to those results for 2019 concerning Mexico City and Mauna Loa site. Both the monthly spectral means of AOD and the monthly means of fine and coarse volume concentration show an increase for the months of January and February 2020 (Volcanic eruption period) compared to the same period in 2019 at Mexico City. Those corresponding to Mauna-Loa seem not sensible with very low values. The effects of ashes of the two-studied volcano are very different, led to a low increase in optical depth comparatively to the contribution of anthropogenic aerosol at MexicoCity (low continental spread) and led to a nonsignificate effect at Mauna-Loa (high marine spread)

Estimation of absorptivity of Earth-atmosphere system over the MENA areas

The developed Annual Columnar Radiative Absorptivity (ACRA19) model that describes, in annual mean, the terrestrial radiation balance of an atmospheric column, allows the determination of the various regional, absorption and reflection of solar and infrared radiation using 2018’s annual data of eight sites in MENA region ( between 22N-38N) of latitude obtained from AERONET and NASA POWER. The atmospheric thermal absorptivity (ATA) is very significant at high temperatures with an average of 0.85±0.1 for 1020 nm and the atmospheric visible absorptivity (AVA) registers 0.36 ± 0.06 when the total optical depth observes its maximum linked to dust aerosol advection